Dear authors, Thank you very much for your ...

2 downloads 0 Views 4MB Size Report
May 8, 2014 - Hu Zhi-Min, Wei Min-Xi, Zhang Ji-Yan, Yi Rong-Qing. Chin. Phys. ..... Shi Ya-Zhou, Wu Yuan-Yan, Wang Feng-Hua and Tan Zhi-Jie. 078702.
home

| Authors

| Referees

| Browse

| Announcement

| Download

| Subscription

| Contact us

| CPS Journals

| Chinese

Dear authors, Thank you very much for your contribution to Chinese Physics B. Your paper has been published in Chinese Physics B, 2014, Vol.23, No.7. Attached is the PDF offprint of your published article, which will be convenient and helpful for your communication with peers and coworkers. Readers can download your published article through our website http://www.iop.org/cpb or http://cpb.iphy.ac.cn What follows is a list of related articles published recently in Chinese Physics B.

Decay pathways of superexcited states of nitrous oxide Lin Mei, Liu Ya-Wei, Zhong Zhi-Ping, Zhu Lin-Fan Chin. Phys. B , 2014, 23(5): 053403.Full Text:

PDF (381KB)

Measurement of integral diffraction coefficients of crystals on beamline 4B7 of Beijing Synchrotron Radiation Facility Yang Jia-Min, Gan Xin-Shi, Zhao Yang, Cui Ming-Qi, Zhu Tuo, Zhao Yi-Dong, Sun Li-Juan, Zheng Lei, Yan Fen, Hu Zhi-Min, Wei Min-Xi, Zhang Ji-Yan, Yi Rong-Qing Chin. Phys. B , 2011, 20(1): 010705.Full Text:

PDF (1160KB)

--------------------------------------------------------------------------------------------------

Chin. Phys. B Vol. 23, No. 7 (2014) 073402 RAPID COMMUNICATION

A double toroidal analyzer for scanning probe electron energy spectrometer∗ Xu Chun-Kai(徐春凯)† , Zhang Pan-Ke(张盼科), Li Meng(郦 盟), and Chen Xiang-Jun(陈向军) Hefei National Laboratory for Physical Science at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China (Received 26 February 2014; revised manuscript received 26 March 2014; published online 8 May 2014)

An ultra-high vacuum (UHV) compatible electron spectrometer employing a double toroidal analyzer has been developed. It is designed to be combined with a custom-made scanning tunneling microscope (STM) to study the spatially localized electron energy spectrum on a surface. A tip–sample system composed of a piezo-driven field-emission tungsten tip and a sample of highly ordered pyrolytic graphite (HOPG) is employed to test the performance of the spectrometer. Two-dimensional images of the energy-resolved and angle-dispersed electrons backscattered from the surface of HOPG are obtained, the performance is optimized and the spectrometer is calibrated. A complete electron energy loss spectrum covering the elastic peak to the secondary electron peaks for the HOPG surface, acquired at a tip voltage of −140 V and a sample current of 0.5 pA, is presented, demonstrating the viability of the spectrometer.

Keywords: double toroidal analyzer, scanning probe electron energy spectroscopy, electron energy loss spectroscopy, secondary electron emission spectroscopy PACS: 34.80.−i, 07.50.Ls, 68.49.Jk

DOI: 10.1088/1674-1056/23/7/073402

1. Introduction

provement, the double toroidal analyzer (DTA), formed by

The spatially localized spectroscopic information from a surface is always attractive to both physicists and chemists. When combined with electron energy loss spectroscopy (EELS), scanning transmission electron microscopy (STEM) is capable of mapping the spatial variation of surface plasmons at the nanoscale [1–5] and even identifying single atoms in nanostructures. [6–9] On the other hand, with the same idea as STEM-EELS, the combination of scanning tunneling microscopy (STM) with EELS – here called scanning probe electron energy spectroscopy (SPEES) – also has a spectrum imaging ability with sub-nanometer spatial resolution. However, early attempts to develop such an instrument encountered great difficulties, [10–14] mainly due to the strong electric field introduced by the tip bias, which greatly compresses the backscattered electrons and reduces the count rate. [15] Therefore, a novel electron energy analyzer with high detection efficiency is required. Toroidal analyzers (TA), which are capable of parallel detections of energies and scattering angles of the charged particles (e.g., electrons) over a large range, have been developed in a variety of fields that have encountered the problem of low count rate. [16–22] The preliminary work of combining a TA with a scanning tip system in our laboratory demonstrated a capability for spatially-resolved spectroscopic measurement by the SPEES technique. [23,24] As a significant im-

juxtaposing two toroidal-sector electrode pairs, has the advantage of achieving a flat focal surface and normal incidence of particles onto the detector surface. This makes the detection efficiency uniform if a planar microchannel-plate detector is used. Moreover, by replacing the complex exit lenses assembly of a normal TA with a pair of concave toroidal electrodes, the DTA improves the performance of the spectrometer and makes the calibration and optimization work much easier. [25–30] In this article, we report an ultra-high vacuum (UHV) compatible electron spectrometer employing the DTA for the SPEES instrument. The performance of the spectrometer is tested using a tip–sample system composed of a piezo-driven field-emission tungsten tip and a sample holder. The backscattered electrons from a highly ordered pyrolytic graphite (HOPG) surface are analyzed by the DTA, and the energy-resolved and angle-dispersed image of the electrons acquired by a two-dimensional position-sensitive detector (PSD) is obtained. The calibration and optimization of the analyzer are carried out, and a complete electron energy loss spectrum is presented, covering the elastic peak to the secondary electron peaks for the HOPG surface, which is acquired at a tip voltage of −140 V and a sample current of 0.5 pA.

∗ Project

supported by the National Basic Research Program of China (Grant No. 2010CB923301) and the National Natural Science Foundation of China (Grant Nos. 11327404 and 11174268). † Corresponding author. E-mail: [email protected] © 2014 Chinese Physical Society and IOP Publishing Ltd http://iopscience.iop.org/cpb   http://cpb.iphy.ac.cn

073402-1

Chin. Phys. B Vol. 23, No. 7 (2014) 073402 2. Instrument The SPEES apparatus is a combination of STM and DTA. The three-dimensional view of the spectrometer is illustrated in Fig. 1(a), in which the DTA and its relative orientation with the STM are shown. Only half of a whole DTA is used in this spectrometer for the purpose of being combined with a custom-made STM. [31] The open side of the DTA is covered by a supporting plate, which is also used as a base board to mount the DTA. The fringe field of the open side is compensated by a series of concentric ring electrodes of gold film printed on the ceramic plates by lithography. The schematic diagram of the cross section containing the cylindrical axis and line A–A0 is shown in Fig. 1(b). In the SPEES experiment, a negative voltage is applied to the STM tip, causing a field emission electron beam incident onto the sample surface. The electrons are backscattered and those moving in the plane parallel to the sample surface are collected, focused, and accelerated/decelerated to the pass energy of the DTA by a fiveelement entrance lens assembly. Each element of the lenses is a pair of ring electrodes, the cross section of which is also illustrated in Fig. 1(b). The electrons passing through the exit aperture of the lenses will enter the double toroidal deflector, which is the juxtaposition of a convex toroidal sector pair with a deflection angle of 180◦ and a concave toroidal sector pair with a deflection angle of 90◦ . This combination will achieve a nearly flat focal plane normal to the direction of electrons at the exit of the second concave toroidal sector. The cylindrical radius a and the spherical radius b are 70 mm and 50 mm, respectively, for each of the two sectors. The deflected electrons are dispersed at the exit of the DTA, where a two-dimensional PSD is placed to detect the outgoing positions of the electrons. The entrance lenses and the deflection sectors are all made of aluminum alloy and mounted on the supporting plate made of nonmagnetic stainless steel. All the surfaces seen by the electrons are coated with gold. The manufacturing precision is about 0.1 mm, and the mounting accuracy is better than 0.1 mm, which is ensured by dowels made of the PEEK material. The PSD consists of two microchannel plates (MCPs) of 80 mm in diameter in a chevron configuration followed by a gear-type resistive anode (RA). However, the effective detection area of the RA used in this apparatus is not large enough to cover the whole exit area of the DTA, we have to sacrifice a small part of the detection azimuthal range, and place the RA eccentrically as shown in Fig. 2. Considering that the data acquired at the edge of the exit area will be discarded due to the fringe electric field effect, this arrangement will barely affect the detection efficiency of the DTA. The voltage supply and signal processing circuitry for the PSD is the same as that in our previous SPEES instrument, which has been reported elsewhere. [23]

The apparatus is mounted in a vacuum chamber made of nonmagnetic stainless steel, which is pumped to an ultra-high vacuum environment of 2.5 × 10−8 Pa by an ion pump. The whole vacuum chamber is covered by a double layer of µ-alloy to shield it from external magnetic fields. (a)

A

DTA

A′ STM

supporting plate compensation electrodes STM guide slide

(b) A

A′ entrance lenses assembly STM

convex toroidal sectors

backscattered electron

shields

supporting plate

concave toroidal sectors PSD Fig. 1. (color online) (a) Three-dimensional view of the SPEES spectrometer. (b) Schematic diagram of the cross section containing the cylindrical axis and line A–A0 .

RAP the exit area of DTA

MCP

Fig. 2. (color online) Orientation of the RA relative to the MCP and the exit area of the DTA.

3. Experimental results Experimental investigations have been carried out to study the electric optics and to optimize the performance of

073402-2

Chin. Phys. B Vol. 23, No. 7 (2014) 073402

Figure 3 shows one of the results of the calibration experiments. During the experiment, the voltage VL5 is scanned from −34 V to −50 V with an interval 2 V, therefore the energy of the electrons entering the DTA varies from 90 eV to 106 eV step by step. The image on the PSD is shown in Fig. 3(a), where a series of concentric arcs can be observed. The electrons with the same energy are supposed to impinge on the arc with the same radius on the PSD. Establishing a polar coordinate with its origin on the center of the arcs, the electron intensity distribution on radius r is calculated and shown in the inset of Fig. 3(a). By fitting this distribution with Gaussian functions, the peak position and the full width at half maximum (FWHM) of each peak can be obtained. The energy dispersion feature of the DTA is represented by the dependence of the electron energy E on its corresponding peak position, which is shown as solid squares in Fig. 3(b). The energy dispersion function is obtained by fitting these data with a quadric curve, which is shown as a solid line in the figure. By employing this function, the electron energy spectrum can be obtained by converting from the measured r-distribution spectrum, and the energy resolution can also be calculated. It is shown as opened circles in Fig. 3(b). To optimize the performance of the DTA, the voltage applied to each element of the entrance lenses, denoted as VL1 , VL2 , VL3 , VL4, and VL5 in order of the electron passing, is adjusted to optimize the performance of the DTA, which means better images of the concentric arcs and thereby better energy resolutions. Among these voltages, VL1 is kept grounded, and VL5 is determined by the incident electron energy and the pass energy of the first toroid. Therefore, three voltages are adjustable. Since it is impossible to test every combination of these three voltages, we just optimize them one by one based on numerical simulations. The final performance of the spectrometer is detailed in Table 1.

Pass energy 1a) 100 eV

Pass energy 2b) 200 eV

Azimuthal range 85◦

Energy resolution 0.89 eV

a) pass

energy of the first pair of toroidal sectors;

b) pass

energy of the second pair of toroidal sectors.

Energy window 16 eV

The performance of the DTA is mostly determined by the point to point focusing feature at a given pass energy. As can be seen in Fig. 3(b), the energy resolution remains almost unchanged in the energy range 92–104 eV, indicating that the point to point focal plane coincides with the PSD detection plane, and the resolution becomes poorer at 90 eV and 106 eV, which is apparently due to the fringe field effect. Compared with our previous SPEES instrument employing a TA, [23] this spectrometer achieves a better energy resolution at the same pass energy, better uniformity, and a wider energy window, which indicates that the incorporation of the DTA has surely improved the performance of the spectrometer. (a)

400 500 600 700 r(channel)

E=141.87462-0.0984r+3.20762T10-5r2 1.3 (b) energy 105 polynomial fit 1.2 energy resolution 1.1 100

1.0 0.9

95

0.8 0.7

90 400

0.6 450

500 550 600 650 Peak center (channel)

Energy resolution/eV

3.1. Calibrations and performance

Table 1. The performance of the DTA.

E/eV

the spectrometer. To do this, we employ a tip–sample system composed of a piezo tip driver and a sample holder. The tip is made from a tungsten wire by electrochemical etching, and the sample is HOPG, the clean surface of which is obtained by cleaving with an adhesive tape. During the experiment, a voltage of −140 V is applied to the tip, while the sample is grounded. The tip is driven to approach the sample surface until a sample current of several picoamps is detected. The elastically backscattered electrons from the HOPG surface are detected and used to test the spectrometer, and the change of the energy E of the electrons entering the DTA is realized by changing the voltage VL5 of the last element of the entrance lenses. The pass energy of the first pair of the toroidal sectors is set to be 100 eV, while that of the second pair is set to be 200 eV to improve the performance of the DTA. [29]

0.5 700

Fig. 3. Calibration of the spectrometer. (a) Two-dimensional image acquired by the PSD at the electron energies from 90 eV to 106 eV with an interval of 2 eV. The electron intensity distribution on radius r is shown in the inset. (b) The energy dispersion function and the energy resolution. See text for details.

Moreover, the apparatus is operated in an UHV environment, resulting in a very stable incident current field-emitted from the tip. Therefore, during the SPEES experiment, the scanning mode, which makes the detection energy range of

073402-3

Chin. Phys. B Vol. 23, No. 7 (2014) 073402 the DTA span the whole energy spectrum, can be employed to eliminate the non-uniform response of the PSD along the r coordinate. 3.2. Complete electron energy loss spectrum of HOPG

SPEES experiments. After being combined with STM, further experiments on localized electron energy loss spectroscopy as well as secondary electron emission spectroscopy can be expected.

A complete electron energy loss spectrum of HOPG, covering the range from zero kinetic energy to zero loss (elastic) energy, is measured in scanning mode to test the performance of this DTA. The acquired spectrum is shown in Fig. 4(a), where we can see clearly both plasmon energy loss and secondary electron emission (SEE) features of the HOPG surface. The details of the spectrum at the low energy loss region (< 60 eV) is shown in the inset of Fig. 4(a), where two peaks due to the plasmon excitation of HOPG are observed. The low-energy-loss peak (∼ 6 eV) is a π plasmon peak, which is assigned to the excitations involving the π electrons only, and the high-energy-loss peak (∼ 22 eV) is a π + σ plasmon peak, which is assigned to the excitations involving all the valence electrons (π and σ ). On the other end of the spectrum, the SEE peaks of graphite are also observed, the detail of which is plotted against the kinetic energy, instead of the energy loss, in the range 0–60 eV in Fig. 4(b). At least five peaks (or shoulders) are observed in the SEE spectrum and are denoted as i–v by arrows. The assignments of the observed peaks based on the critical points in the theoretically calculated unoccupied band structure of graphite [32] are summarized in Table 2. The values are given relative to the Fermi level. The measurement of the complete energy loss spectrum of HOPG indicates that this DTA can meet the requirements of

(a)

π+σ

Intensity

π

0

0

10 20 30 40 50 60

20

ii

60 80 100 40 Energy loss/eV

120

140

(b)

iii

Intensity

iv v

i

0

10

20

30

40

50

60

Kinetic energy/eV Fig. 4. (a) Complete electron energy loss spectrum of HOPG as obtained by the SPEES instrument. (b) Detail of the low-kineticenergy region of the spectrum in panel (a).

Table 2. The assignment of the SEE peaks observed in Fig. 4(b). Peak i ii iii iv v

Band assignment π(M− 4) π(Λ2 ) − − + σ (Γ+ 1 /Γ6 /M1 /M2 ) − + σ (Γ1 /Γ4 ) π(M− 4)

Experimental/eV (in Fig. 4) 1.7 5.7 7.4 12.7 27.0

4. Summary In summary, we have developed a double toroidal analyzer (DTA), which is designed to be employed in an SPEES instrument. The calibration and the optimization have been carried out with a tip–sample system composed of a piezodriven field-emission tungsten tip and a sample of cleaved HOPG surface, and the performance of the DTA has been tested. A complete electron energy loss spectrum of HOPG is acquired, which shows both energy loss features due to the plasmon excitation in the low energy loss region and the secondary electron emission features in the low kinetic energy

Theory/eV (Ref. [30]) 1.74(M− 4) 6.04(Λ2 ) − − + 7.35 (Γ+ 1 /Γ6 )/7.30 (M1 )/7.45 (M2 ) − + 13.16 (Γ1 /Γ4 ) 27.19 (M− 4)

region. This result indicates that this DTA is capable of fitting the SPEES instrument, and future work can be expected, combining it with STM.

References [1] Bosman M, Keast V J, Watanabe M, Maaroof A I and Cortie M B 2007 Nanotechnology 18 165505 [2] Nelayah J, Kociak M, St´ephan O, Abajo F J G, Tenc´e M, Henrard L, Taverna D, Pastoriza-Santos I, Liz-Marz´an L M and Colliex C 2007 Nat. Phys. 3 348 [3] Chu M W, Chen C H, Garc´ıa de Abajo F J, Deng J P and Mou C Y 2008 Phys. Rev. B 77 245402 [4] Koh A L, Bao K, Khan I, Smith W E, Kothleitner G, Nordlander P, Maier S A and McComb D W 2009 ACS Nano 3 3015

073402-4

Chin. Phys. B Vol. 23, No. 7 (2014) 073402 [5] Nicoletti O, Pena F, Leary R K, Holland D J, Ducati C and Midgley P A 2013 Nature 502 80 [6] Suenaga K, Tenc´e M, Mory C, Colliex C, Kato H, Okazaki T, Shinohara H, Hirahara K, Bandow S and Iijima S 2000 Scinece 290 2280 [7] Pennycook S J, Varela M, Lupini A R, Oxley M P and Chisholm M F 2009 J. Electron Microsc. 58 87 [8] Suenaga K, Hasegawa K A, Niimi Y, Kobayashi H, Nakamura M, Liu Z, Sato Yuta, Koshino M and Iijima S 2012 J. Electron Microsc. 61 285 [9] Zhou W, Oxley M P, Lupini A R, Krivanek O L, Pennycook S J and Idrobo J C 2012 Microsc. Microanal. 18 1342 [10] Tomitori M, Hirade M, Suganuma Y and Arai T 2001 Surf. Sci. 493 49 [11] Miyatake Y, Nagamura T, Hattori K, Kannemitsu Y and Daimon H 2003 Jpn. J. Appl. Phys. 42 4848 [12] Palmer R E, Eves B J and Festy F 2002 Surf. Sci. 502 224 [13] Festy F and Palmer R E 2004 Appl. Phys. Lett. 85 5034 [14] Song M Y, Lawton J J, Robinson A P G and Palmer R E 2010 Phys. Rev. B 81 161411 [15] Liu W J, Xu C K, Li Y G, Ding Z J, Xu K Z and Chen X J 2009 Jpn. J. Appl. Phys. 48 122301 [16] Engelhardt H A, Black W, Menzel D and Liebl H 1981 Rev. Sci. Instrum. 52 835 [17] Leckey R C G 1987 J. Electron Spectrosc. Relat. Phenom. 43 183 [18] Huetz A, Lablanquie P, Andric L, Selles P and Mazeau J 1994 J. Phys. B 27 L13

[19] Reddish T J, Richmond G, Bagley G W, Wightman J P and Cvejanovic S 1997 Rev. Sci. Instrum. 68 2685 [20] Berger D, Filippov M, Niedrig H, Rau E I and Schlichting F 1999 J. Electron Spectrosc. Relat. Phenom. 105 119 [21] Siggel-King M R F, Lindsay R, Quinn F M, Pearson J, Fraser G and Thornton G 2004 J. Electron Spectrosc. Relat. Phenom. 137–140 721 [22] Boeyen R W and Williams J F 2005 Rev. Sci. Instrum. 76 063303 [23] Zhou X, Xu C K, Wei Z, Liu W J, Li J W, Chen X J, Williams J F and Xu K Z 2008 J. Electron Spectrosc. Relat. Phenom. 165 15 [24] Xu C K, Chen X J, Zhou X, Wei Z, Liu W J, Li J W, Williams J F and Xu K Z 2009 Rev. Sci. Instrum. 80 103705 [25] Toffoletto F, Leckey R C G and Riley J D 1985 Nucl. Instrum. Methods Phys. Res. B 12 282 [26] Hellings G J A, Ottevanger H, Knibbeler C L C M, Engelshoven J and Brongersma H H 1989 J. Electron Spectrosc. Relat. Phenom. 49 359 [27] Miron C, Simon M, Leclercq N and Morin P 1997 Rev. Sci. Instrum. 68 3728 [28] Ren X G, Ning C G, Deng J K, Zhang S F, Su G L, Huang F and Li G Q 2005 Rev. Sci. Instrum. 76 063103 [29] Lower J, Panajotovic R, Bellm S and Weigold E 2007 Rev. Sci. Instrum. 78 111301 [30] Zhang P K, Xu C K, Tang Y G and Chen X J 2014 J. Electron Spectrosc. Relat. Phenom. 193 39 [31] Hou Y B, Wang J H and Lu Q Y 2008 Rev. Sci. Instrum. 79 113707 [32] Tatar R C and Rabii S 1982 Phys. Rev. B 25 4126

073402-5

Chinese Physics B Volume 23

Number 7

July 2014

TOPICAL REVIEW — Magnetism, magnetic materials, and interdisciplinary research 077308

Exotic electronic states in the world of flat bands: From theory to material Liu Zheng, Liu Feng and Wu Yong-Shi

077501

Perpendicular magnetic tunnel junction and its application in magnetic random access memory Liu Hou-Fang, Syed Shahbaz Ali and Han Xiu-Feng

078704

Formation of multifunctional Fe3 O4 /Au composite nanoparticles for dual-mode MR/CT imaging applications Hu Yong, Li Jing-Chao, Shen Ming-Wu and Shi Xiang-Yang TOPICAL REVIEW — Statistical physics and complex systems

070501

Nonequilibrium thermodynamics and fluctuation relations for small systems Cao Liang, Ke Pu, Qiao Li-Yan and Zheng Zhi-Gang

070507

Level spacing statistics for two-dimensional massless Dirac billiards Huang Liang, Xu Hong-Ya, Lai Ying-Cheng and Celso Grebogi

070512

Nonequilibrium work equalities in isolated quantum systems Liu Fei and Ouyang Zhong-Can

070513

Equivalent formulations of “the equation of life” Ao Ping

070514

Sub-diffusive scaling with power-law trapping times Luo Liang and Tang Lei-Han

074501

Effective temperature and fluctuation-dissipation relation in athermal granular systems: A review Chen Qiong and Hou Mei-Ying

076402

Percolation on networks with dependence links Li Ming and Wang Bing-Hong

078701

RNA structure prediction: Progress and perspective Shi Ya-Zhou, Wu Yuan-Yan, Wang Feng-Hua and Tan Zhi-Jie

078702

Collective behaviors of suprachiasm nucleus neurons under different light–dark cycles Gu Chang-Gui, Zhang Xin-Hua and Liu Zong-Hua

078705

Proteins: From sequence to structure Zheng Wei-Mou

078901

Statistical physics of hard combinatorial optimization: Vertex cover problem

078902

Zhao Jin-Hua and Zhou Hai-Jun Statistical physics of human beings in games: Controlled experiments Liang Yuan and Huang Ji-Ping (Continued on the Bookbinding Inside Back Cover)

078903

A mini-review on econophysics: Comparative study of Chinese and western financial markets Zheng Bo, Jiang Xiong-Fei and Ni Peng-Yun

078905

Zero-determinant strategy: An underway revolution in game theory Hao Dong, Rong Zhi-Hai and Zhou Tao

078906

Attractive target wave patterns in complex networks consisting of excitable nodes Zhang Li-Sheng, Liao Xu-Hong, Mi Yuan-Yuan, Qian Yu and Hu Gang RAPID COMMUNICATION

073402

A double toroidal analyzer for scanning probe electron energy spectrometer Xu Chun-Kai, Zhang Pan-Ke, Li Meng and Chen Xiang-Jun

077505

Multiferroic properties in terbium orthoferrite Song Yu-Quan, Zhou Wei-Ping, Fang Yong, Yang Yan-Ting, Wang Liao-Yu, Wang Dun-Hui and Du You-Wei GENERAL

070201

Symmetries and variational calculation of discrete Hamiltonian systems Xia Li-Li, Chen Li-Qun, Fu Jing-Li and Wu Jing-He

070202

Non-autonomous discrete Boussinesq equation: Solutions and consistency Nong Li-Juan and Zhang Da-Juan

070203

Rogue-wave pair and dark-bright-rogue wave solutions of the coupled Hirota equations Wang Xin and Chen Yong

070204

Optimal switching policy for performance enhancement of distributed parameter systems based on event-driven control Mu Wen-Ying, Cui Bao-Tong, Lou Xu-Yang and Li Wen

070205

Impulsive effect on exponential synchronization of neural networks with leakage delay under sampleddata feedback control S. Lakshmanan, Ju H. Park, Fathalla A. Rihan and R. Rakkiyappan

070206

Co-evolution of the brand effect and competitiveness in evolving networks

070207

Guo Jin-Li An interpolating reproducing kernel particle method for two-dimensional scatter points Qin Yi-Xiao, Liu Ying-Ying, Li Zhong-Hua and Yang Ming

070208

Average vector field methods for the coupled Schr¨odinger KdV equations Zhang Hong, Song Song-He, Chen Xu-Dong and Zhou Wei-En

070301

Comparison between photon annihilation-then-creation and photon creation-then-annihilation thermal states: Non-classical and non-Gaussian properties Xu Xue-Xiang, Yuan Hong-Chun and Wang Yan

070302

Global entanglement in ground state of {Cu3 } single-molecular magnet with magnetic field Li Ji-Qiang and Zhou Bin

070303

Rise of quantum correlations in non-Markovian environments in continuous-variable systems

070304

Liu Xin and Wu Wei Optimal 1 → 𝑀 phase-covariant cloning in three dimensions Zhang Wen-Hai, Yu Long-Bao, Cao Zhuo-Liang and Ye Liu

(Continued on the Bookbinding Inside Back Cover) 070305

Symmetric quantum discord for a two-qubit state Wang Zhong-Xiao and Wang Bo-Bo

070306

Quantum correlations in a two-qubit anisotropic Heisenberg XY Z chain with uniform magnetic field Li Lei and Yang Guo-Hui

070307

Adiabatic tunneling of Bose–Einstein condensates with modulated atom interaction in a double-well potential Xin Xiao-Tian, Huang Fang, Xu Zhi-Jun and Li Hai-Bin

070308

Ground state of rotating ultracold quantum gases with anisotropic spin orbit coupling and concentrically coupled annular potential Wang Xin, Tan Ren-Bing, Du Zhi-Jing, Zhao Wen-Yu, Zhang Xiao-Fei and Zhang Shou-Gang

070502

Delay-dependent asymptotic stability of mobile ad-hoc networks: A descriptor system approach Yang Juan, Yang Dan, Huang Bin, Zhang Xiao-Hong and Luo Jian-Lu

070503

Mapping equivalent approach to analysis and realization of memristor-based dynamical circuit Bao Bo-Cheng, Hu Feng-Wei, Liu Zhong and Xu Jian-Ping

070504

Signal reconstruction in wireless sensor networks based on a cubature Kalman particle filter Huang Jin-Wang and Feng Jiu-Chao

070505

Space time fractional KdV Burgers equation for dust acoustic shock waves in dusty plasma with nonthermal ions Emad K. El-Shewy, Abeer A. Mahmoud, Ashraf M. Tawfik, Essam M. Abulwafa and Ahmed Elgarayhi

070506

PC synchronization of a class of chaotic systems via event-triggered control Luo Run-Zi and He Long-Min

070508

Partial and complete periodic synchronization in coupled discontinuous map lattices Yang Ke-Li, Chen Hui-Yun, Du Wei-Wei, Jin Tao and Qu Shi-Xian

070509

Distributed formation control for a multi-agent system with dynamic and static obstacle avoidances Cao Jian-Fu, Ling Zhi-Hao, Yuan Yi-Feng and Gao Chong

070510

Fault-tolerant topology in the wireless sensor networks for energy depletion and random failure Liu Bin, Dong Ming-Ru, Yin Rong-Rong and Yin Wen-Xiao

070511

Nonequilibrium behavior of the kinetic metamagnetic spin-5/2 Blume–Capel model

070701

¨ ut Temizer Um¨ Ferromagnetic materials under high pressure in a diamond-anvil cell: A magnetic study Wang Xin, Hu Tian-Li, Han Bing, Jin Hui-Chao, Li Yan, Zhou Qiang and Zhang Tao

070702

Mutator for transferring a memristor emulator into meminductive and memcapacitive circuits Yu Dong-Sheng, Liang Yan, Herbert H. C. Iu and Hu Yi-Hua ATOMIC AND MOLECULAR PHYSICS

073101

2 3 A typical slow reaction H(2 S) + S2 (𝑋 3 Σ− g ) → SH(𝑋 Π) + S( P) on a new surface: Quantum dynamics

calculations Wei Wei, Gao Shou-Bao, Sun Zhao-Peng, Song Yu-Zhi and Meng Qing-Tian (Continued on the Bookbinding Inside Back Cover)

073201

On-chip optical pulse shaper for arbitrary waveform generation Liao Sha-Sha, Yang Ting and Dong Jian-Ji

073301

Dynamical correlation between quantum entanglement and intramolecular energy in molecular vibrations: An algebraic approach Feng Hai-Ran, Meng Xiang-Jia, Li Peng and Zheng Yu-Jun

073401

Potential energy curves and spectroscopic properties of X2 Σ+ and A2 Π states of 13 C14 N Liao Jian-Wen and Yang Chuan-Lu ELECTROMAGNETISM, OPTICS, ACOUSTICS, HEAT TRANSFER, CLASSICAL MECHANICS, AND FLUID DYNAMICS

074101

A progressive processing method for breast cancer detection via UWB based on an MRI-derived model Xiao Xia, Song Hang, Wang Zong-Jie and Wang Liang

074201

Solar-blind ultraviolet band-pass filter based on metal–dielectric multilayer structures Wang Tian-Jiao, Xu Wei-Zong, Lu Hai, Ren Fang-Fang, Chen Dun-Jun, Zhang Rong and Zheng You-Dou

074202

Scintillation of partially coherent Gaussian–Schell model beam propagation in slant atmospheric turbulence considering inner- and outer-scale effects Li Ya-Qing, Wu Zhen-Sen, Zhang Yuan-Yuan and Wang Ming-Jun

074203

Entropy squeezing and atomic inversion in the 𝑘-photon Jaynes–Cummings model in the presence of the Stark shift and a Kerr medium: A full nonlinear approach H R Baghshahi, M K Tavassoly and A Behjat

074204

Electromagnetically induced grating in a four-level tripod-type atomic system Dong Ya-Bin and Guo Yao-Hua

074205

Application of thermal stress model to paint removal by Q-switched Nd:YAG laser Zou Wan-Fang, Xie Ying-Mao, Xiao Xing, Zeng Xiang-Zhi and Luo Ying

074206

All optical method for measuring the carrier envelope phase from half-cycle cutoffs Li Qian-Guang, Chen Huan, Zhang Xiu and Yi Xu-Nong

074207

Spectral energetic properties of the X-ray-boosted photoionization by an intense few-cycle laser Ge Yu-Cheng and He Hai-Ping

074208

Transversal reverse transformation of anomalous hollow beams in strongly isotropic nonlocal media Dai Zhi-Ping, Yang Zhen-Jun, Zhang Shu-Min, Pang Zhao-Guang and You Kai-Min

074209

Phase transition model of water flow irradiated by high-energy laser in a chamber Wei Ji-Feng, Sun Li-Qun, Zhang Kai and Hu Xiao-Yang

074301

Nonlinear impedances of thermoacoustic stacks with ordered and disordered structures Ge Huan, Fan Li, Xia Jie, Zhang Shu-Yi, Tao Sha, Yang Yue-Tao and Zhang Hui

074302

Integrated physics package of a chip-scale atomic clock Li Shao-Liang, Xu Jing, Zhang Zhi-Qiang, Zhao Lu-Bing, Long Liang and Wu Ya-Ming

074401

Flow and heat transfer of a nanofluid over a hyperbolically stretching sheet A. Ahmad, S. Asghar and A. Alsaedi (Continued on the Bookbinding Inside Back Cover)

074701

Three-dimensional magnetohydrodynamics axisymmetric stagnation flow and heat transfer due to an axisymmetric shrinking/stretching sheet with viscous dissipation and heat source/sink Dinesh Rajotia and R. N. Jat

074702

Molecular dynamics simulations of the nano-droplet impact process on hydrophobic surfaces Hu Hai-Bao, Chen Li-Bin, Bao Lu-Yao and Huang Su-He

074703

Influence of limestone fillers on combustion characteristics of asphalt mortar for pavements Wu Ke, Zhu Kai, Wu Hao, Han Jun, Wang Jin-Chang, Huang Zhi-Yi and Liang Pei PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES

075201

Balmer-alpha and Balmer-beta Stark line intensity profiles for high-power hydrogen inductively coupled plasmas Wang Song-Bai, Lei Guang-Jiu, Liu Dong-Ping and Yang Si-Ze

075202

Mitigation of energetic ion debris from Gd plasma using dual laser pulses and the combined effect with ambient gas Dou Yin-Ping, Sun Chang-Kai, Liu Chao-Zhi, Gao Jian, Hao Zuo-Qiang and Lin Jing-Quan

075203

Characteristics of wall sheath and secondary electron emission under different electron temperatures in a Hall thruster Duan Ping, Qin Hai-Juan, Zhou Xin-Wei, Cao An-Ning, Chen Long and Gao Hong

075204

Atmospheric pressure plasma jet utilizing Ar and Ar/H2 O mixtures and its applications to bacteria inactivation Cheng Cheng, Shen Jie, Xiao De-Zhi, Xie Hong-Bing, Lan Yan, Fang Shi-Dong, Meng Yue-Dong and Chu Paul K

075205

Effect of passive structure and toroidal rotation on resistive wall mode stability in the EAST tokamak Liu Guang-Jun, Wan Bao-Nian, Sun You-Wen, Liu Yue-Qiang, Guo Wen-Feng, Hao Guang-Zhou, Ding Si-Ye, Shen Biao, Xiao Bing-Jia and Qian Jin-Ping

075206

Toroidicity and shape dependence of peeling mode growth rates in axisymmetric toroidal plasmas Shi Bing-Ren

075207

DD proton spectrum for diagnosing the areal density of imploded capsules on Shenguang III prototype laser facility Teng Jian, Zhang Tian-Kui, Wu Bo, Pu Yu-Dong, Hong Wei, Shan Lian-Qiang, Zhu Bin, He Wei-Hua, Lu Feng, Wen Xian-Lun, Zhou Wei-Min, Cao Lei-Feng, Jiang Shao-En and Gu Yu-Qiu

075208

Efficiency and stability enhancement of a virtual cathode oscillator Fan Yu-Wei, Li Zhi-Qiang, Shu Ting and Liu Jing

075209

Mode transition in homogenous dielectric barrier discharge in argon at atmospheric pressure Liu Fu-Cheng, He Ya-Feng and Wang Xiao-Fei

075210

Shockwave–boundary layer interaction control by plasma aerodynamic actuation: An experimental investigation Sun Quan, Cui Wei, Li Ying-Hong, Cheng Bang-Qin, Jin Di and Li Jun (Continued on the Bookbinding Inside Back Cover)

CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES 076101

Small-angle X-ray analysis of the effect of grain size on the thermal damage of octahydro-1, 3, 5, 7tetranitro-1, 3, 5, 7 tetrazocine-based plastic-bounded expolsives Yan Guan-Yun, Tian Qiang, Liu Jia-Hui, Chen Bo, Sun Guang-Ai, Huang Ming and Li Xiu-Hong

076102

Quantum confinement and surface chemistry of 0.8–1.6 nm hydrosilylated silicon nanocrystals Pi Xiao-Dong, Wang Rong and Yang De-Ren

076103

Spectroscopic and scanning probe analysis on large-area epitaxial graphene grown under pressure of 4 mbar on 4H-SiC (0001) substrates Wang Dang-Chao and Zhang Yu-Ming

076104

Ferromagnetism on a paramagnetic host background in cobalt-doped Bi2 Se3 topological insulator Zhang Min, L¨u Li, Wei Zhan-Tao, Yang Xin-Sheng and Zhao Yong

076105

Physical properties of FePt nanocomposite doped with Ag atoms: First-principles study Jia Yong-Fei, Shu Xiao-Lin, Xie Yong and Chen Zi-Yu

076301

Effect of size polydispersity on the structural and vibrational characteristics of two-dimensional granular assemblies Zhang Guo-Hua, Sun Qi-Cheng, Shi Zhi-Ping, Feng Xu, Gu Qiang and Jin Feng

076401

Characteristics of phase transitions via intervention in random networks Jia Xiao, Hong Jin-Song, Yang Hong-Chun, Yang Chun, Shi Xiao-Hong and Hu Jian-Quan

076403

Electrical and optical properties of indium tin oxide/epoxy composite film Guo Xia, Guo Chun-Wei, Chen Yu and Su Zhi-Ping

076501

Dynamic thermo-mechanical coupled response of random particulate composites: A statistical two-scale method Yang Zi-Hao, Chen Yun, Yang Zhi-Qiang and Ma Qiang

076801

Fabrication of VO2 thin film by rapid thermal annealing in oxygen atmosphere and its metal–insulator phase transition properties Liang Ji-Ran, Wu Mai-Jun, Hu Ming, Liu Jian, Zhu Nai-Wei, Xia Xiao-Xu and Chen Hong-Da CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES

077101

Interaction and spin–orbit effects on a kagome lattice at 1/3 filling Liu Hai-Di, Chen Yao-Hua, Lin Heng-Fu, Tao Hong-Shuai and Wu Jian-Hua

077102

First-principles study of structural, electronic and optical properties of ZnF2 Wu Jian-Bang, Cheng Xin-Lu, Zhang Hong and Xiong Zheng-Wei

077103

Hybrid density functional studies of cadmium vacancy in CdTe Xu Run), Xu Hai-Tao, Tang Min-Yan and Wang Lin-Jun

077104

A theoretical investigation of the band alignment of type-I direct band gap dilute nitride phosphide alloy of GaNx Asy P1−x−y /GaP quantum wells on GaP substrates ¨ L Unsal, ¨ O B G¨on¨ul and M Temiz (Continued on the Bookbinding Inside Back Cover)

077105

Influence of temperature on strain-induced polarization Coulomb field scattering in AlN/GaN heterostructure field-effect transistors L¨u Yuan-Jie, Feng Zhi-Hong, Lin Zhao-Jun, Guo Hong-Yu, Gu Guo-Dong, Yin Jia-Yun, Wang Yuan-Gang, Xu Peng, Song Xu-Bo and Cai Shu-Jun

077201

Design consideration and fabrication of 1.2-kV 4H-SiC trenched-and-implanted vertical junction fieldeffect transistors Chen Si-Zhe and Sheng Kuang

077202

A novel solution-based self-assembly approach to preparing ultralong titanyl phthalocyanine sub-micron wires Zhu Zong-Peng, Wei Bin, Zhang Jian-Hua and Wang Jun

077301

Lattice structures and electronic properties of CIGS/CdS interface: First-principles calculations Tang Fu-Ling, Liu Ran, Xue Hong-Tao, Lu Wen-Jiang, Feng Yu-Dong, Rui Zhi-Yuan, and Huang Min

077302

Efficiency of electrical manipulation in two-dimensional topological insulators Pang Mi and Wu Xiao-Guang

077303

Effect of annealing on performance of PEDOT:PSS/n-GaN Schottky solar cells Feng Qian, Du Kai, Li Yu-Kun, Shi Peng and Feng Qing

077304

Non-recessed-gate quasi-E-mode double heterojunction AlGaN/GaN high electron mobility transistor with high breakdown voltage Mi Min-Han, Zhang Kai, Chen Xing, Zhao Sheng-Lei, Wang Chong, Zhang Jin-Cheng, Ma Xiao-Hua and Hao Yue

077305

Effect of alumina thickness on Al2 O3 /InP interface with post deposition annealing in oxygen ambient Yang Zhuo, Yang Jing-Zhi, Huang Yong, Zhang Kai and Hao Yue

077306

A low specific on-resistance SOI LDMOS with a novel junction field plate Luo Yin-Chun, Luo Xiao-Rong, Hu Gang-Yi, Fan Yuan-Hang, Li Peng-Cheng, Wei Jie, Tan Qiao and Zhang Bo

077307

High dV /dt immunity MOS controlled thyristor using a double variable lateral doping technique for capacitor discharge applications Chen Wan-Jun, Sun Rui-Ze, Peng Chao-Fei and Zhang Bo

077401

Formation of epitaxial Tl2 Ba2 Ca2 Cu3 O10 superconducting films by dc-magnetron sputtering and triple post-annealing method Xie Wei, Wang Pei, Ji Lu, Ge De-Yong, Du Jia-Nan, Gao Xiao-Xin, Liu Xin, Song Feng-Bin, Hu Lei, Zhang Xu, He Ming and Zhao Xin-Jie

077502

Modulation of magnetic properties and enhanced magnetoelectric effects in MnW1−𝑥 Mo𝑥 O4 compounds Fang Yong, Zhou Wei-Ping, Song Yu-Quan, L¨u Li-Ya, Wang Dun-Hui and Du Yu Wei

077503

Substituting Al for Fe in Pr(Al𝑥 Fe1−𝑥 )1.9 alloys: Effects on magnetic and magnetostrictive properties Tang Yan-Mei, Chen Le-Yi, Wei Jun, Tang Shao-Long and Du You-Wei

(Continued on the Bookbinding Inside Back Cover)

077504

Degradation of ferroelectric and weak ferromagnetic properties of BiFeO3 films due to the diffusion of silicon atoms Xiao Ren-Zheng, Zhang Zao-Di, Vasiliy O. Pelenovich, Wang Ze-Song, Zhang Rui, Li Hui, Liu Yong, Huang Zhi-Hong and Fu De-Jun

077601

An electron spin resonance study of Eu doping effect in La4/3 Sr5/3 Mn2 O7 single crystal He Li-Min, Ji Yu, Wu Hong-Ye, Xu Bao, Sun Yun-Bin, Zhang Xue-Feng, Lu Yi and Zhao Jian-Jun

077801

What has been measured by reflection magnetic circular dichroism in Ga1−𝑥 Mn𝑥 As/GaAs structures? He Zhen-Xin, Zheng Hou-Zhi, Huang Xue-Jiao, Wang Hai-Long and Zhao Jian-Hua

077802

Pure blue and white light electroluminescence in a multilayer organic light-emitting diode using a new blue emitter Wei Na, Guo Kun-Ping, Zhou Peng-Chao, Yu Jian-Ning, Wei Bin and Zhang Jian-Hua

077901

Self-organized voids revisited: Experimental verification of the formation mechanism Song Juan, Ye Jun-Yi, Qian Meng-Di, Luo Fang-Fang, Lin Xian, Bian Hua-Dong, Dai Ye, Ma Guo-Hong, Chen Qing-Xi, Jiang Yan, Zhao Quan-Zhong and Qiu Jian-Rong INTERDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY

078101

Microwave absorption properties of a double-layer absorber based on nanocomposite BaFe12 O19 /α-Fe and nanocrystalline α-Fe microfibers Shen Xiang-Qian, Liu Hong-Bo, Wang Zhou, Qian Xin-Ye, Jing Mao-Xiang and Yang Xin-Chun

078102

Improved interfacial and electrical properties of GaSb metal oxide semiconductor devices passivated with acidic (NH4 )2 S solution Zhao Lian-Feng, Tan Zhen, Wang Jing and Xu Jun

078401

Hybrid phase-locked loop with fast locking time and low spur in a 0.18-µm CMOS process Zhu Si-Heng, Si Li-Ming, Guo Chao, Shi Jun-Yu and Zhu Wei-Ren

078402

Four-dimensional parameter estimation of plane waves using swarming intelligence Fawad Zaman, Ijaz Mansoor Qureshi, Fahad Munir and Zafar Ullah Khan

078703

Image reconstruction from few views by ℓ0 -norm optimization

078904

Sun Yu-Li and Tao Jin-Xu Row–column visibility graph approach to two-dimensional landscapes Xiao Qin, Pan Xue, Li Xin-Li, Mutua Stephen, Yang Hui-Jie, Jiang Yan, Wang Jian-Yong and Zhang Qing-Jun GEOPHYSICS, ASTRONOMY, AND ASTROPHYSICS

079401

Experimental verification of the parasitic bipolar amplification effect in PMOS single event transients He Yi-Bai and Chen Shu-Ming