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Structural evolution and bandgap modulation of layered β-GeSe₂ single crystal under high pressure

Hengli Xie(谢恒立), Jiaxiang Wang(王家祥), Lingrui Wang(王玲瑞), Yong Yan(闫勇), Juan Guo(郭娟), Qilong Gao(高其龙), Mingju Chao(晁明举), Erjun Liang(梁二军), and Xiao Ren(任霄)

Chin. Phys. B, 2022, 31 (7): 076101. DOI: 10.1088/1674-1056/ac6db8

Abstract （544）

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Germanium diselenide (GeSe₂) is a promising candidate for electronic devices because of its unique crystal structure and optoelectronic properties. However, the evolution of lattice and electronic structure of $β$-GeSe₂ at high pressure is still uncertain. Here we prepared high-quality $β$-GeSe₂ single crystals by chemical vapor transfer (CVT) technique and performed systematic experimental studies on the evolution of lattice structure and bandgap of $β$-GeSe₂ under pressure. High-precision high-pressure ultra low frequency (ULF) Raman scattering and synchrotron angle-dispersive x-ray diffraction (ADXRD) measurements support that no structural phase transition exists under high pressure up to 13.80 GPa, but the structure of $β$-GeSe₂ turns into a disordered state near 6.91 GPa and gradually becomes amorphous forming an irreversibly amorphous crystal at 13.80 GPa. Two Raman modes keep softening abnormally upon pressure. The bandgap of $β$-GeSe₂ reduced linearly from 2.59 eV to 1.65 eV under pressure with a detectable narrowing of 36.5%, and the sample under pressure performs the piezochromism phenomenon. The bandgap after decompression is smaller than that in the atmospheric pressure environment, which is caused by incomplete recrystallization. These results enrich the insight into the structural and optical properties of $β$-GeSe₂ and demonstrate the potential of pressure in modulating the material properties of two-dimensional (2D) Ge-based binary material.

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Radiation effects of electrons on multilayer FePS₃ studied with laser plasma accelerator

Meng Peng(彭猛), Jun-Bo Yang(杨俊波), Hao Chen(陈浩), Bo-Yuan Li(李博源), Xu-Lei Ge(葛绪雷), Xiao-Hu Yang(杨晓虎), Guo-Bo Zhang(张国博), and Yan-Yun Ma(马燕云)

Chin. Phys. B, 2022, 31 (8): 086102. DOI: 10.1088/1674-1056/ac5c34

Abstract （540）

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Space radiation with inherently broadband spectral flux poses a huge danger to astronauts and electronics on aircraft, but it is hard to simulate such feature with conventional radiation sources. Using a tabletop laser-plasma accelerator, we can reproduce exponential energy particle beams as similar as possible to these in space radiation. We used such an electron beam to study the electron radiation effects on the surface structure and performance of two-dimensional material (FePS₃). Energetic electron beam led to bulk sample cleavage and damage between areas of uneven thickness. For the FePS₃ sheet sample, electron radiation transformed it from crystalline state to amorphous state, causing the sample surface to rough. The full widths at the half maximum of characteristic Raman peaks became larger, and the intensities of characteristic Raman peaks became weak or even disappeared dramatically under electron radiation. This trend became more obvious for thinner samples, and this phenomenon was attributed to the cleavage of P-P and P-S bonds, destabilizing the bipyramid structure of [P₂S₆]^4- unit. The results are of great significance for testing the maximum allowable radiation dose for the two-dimensional material, implying that FePS₃ cannot withstand such energetic electron radiation without an essential shield.

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Bandgap evolution of Mg₃N₂ under pressure: Experimental and theoretical studies

Gang Wu(吴刚), Lu Wang(王璐), Kuo Bao(包括), Xianli Li(李贤丽), Sheng Wang(王升), and Chunhong Xu(徐春红)

Chin. Phys. B, 2022, 31 (6): 066205. DOI: 10.1088/1674-1056/ac4cbe

Abstract （453）

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Wide bandgap semiconductors are crucially significant for optoelectronic and thermoelectric device applications. Metal nitride is a class of semiconductor material with great potential. Under high pressure, the bandgap of magnesium nitride was predicted to grow. Raman spectra, ultra-violet-visible (UV-Vis) absorption spectra, and first-principles calculations were employed in this study to analyze the bandgap evolution of Mg₃N₂. The widening of the bandgap has been first detected experimentally, with the gap increasing from 2.05 eV at 3 GPa to 2.88 eV at 47 GPa. According to the calculation results, the enhanced covalent component is responsible for the bandgap widening.

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Theoretical and experimental studies on high-power laser-induced thermal blooming effect in chamber with different gases

Xiangyizheng Wu(吴祥议政), Jian Xu(徐健), Keling Gong(龚柯菱), Chongfeng Shao(邵崇峰), Yang Kou(寇洋), Yuxuan Zhang(张宇轩), Yong Bo(薄勇), and Qinjun Peng(彭钦军)

Chin. Phys. B, 2022, 31 (8): 086105. DOI: 10.1088/1674-1056/ac6165

Abstract （436）

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High-power laser induced thermal blooming effects in a closed chamber with three different gases are investigated theoretically and experimentally in this work. In the theoretical treatment, an incompressible gas turbulent model is adopted. In the numerical simulation the gas refractive index as a function of both the temperature and pressure is taken into consideration. In the experimental study the pump-probe technology is adopted. A high-power 1064-nm fiber laser with maximum output power of 12 kW is used to drive the gas thermal blooming, and a 50-mW high-beam-quality 637-nm laser diode (LD) is used as a probe beam. The influences of the gas thermal blooming in the chamber on the probe beam wavefront and beam quality are analyzed for three different gases of air, nitrogen, and helium, respectively. The results indicate that nitrogen is well suitable for restraining thermal blooming effect for high-power laser. The measured data are in good agreement with the simulated results.

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Microstructure and hardening effect of pure tungsten and ZrO₂ strengthened tungsten under carbon ion irradiation at 700℃

Chun-Yang Luo(罗春阳), Bo Cui(崔博), Liu-Jie Xu(徐流杰), Le Zong(宗乐), Chuan Xu(徐川), En-Gang Fu(付恩刚), Xiao-Song Zhou(周晓松), Xing-Gui Long(龙兴贵), Shu-Ming Peng(彭述明), Shi-Zhong Wei(魏世忠), and Hua-Hai Shen(申华海)

Chin. Phys. B, 2022, 31 (9): 096102. DOI: 10.1088/1674-1056/ac6b25

Abstract （376）

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Microstructure evolution and hardening effect of pure tungsten and W-1.5%ZrO₂ alloy under carbon ion irradiation are investigated by using transmission electron microscopy and nano-indentation. Carbon ion irradiation is performed at 700 ℃ with irradiation damages ranging from 0.25 dpa to 2.0 dpa. The results show that the irradiation defect clusters are mainly in the form of dislocation loop. The size and density of dislocation loops increase with irradiation damages intensifying. The W-1.5%ZrO₂ alloy has a smaller dislocation loop size than that of pure tungsten. It is proposed that the phase boundaries have the ability to absorb and annihilate defects and the addition of ZrO₂ phase improves the sink strength for irradiation defects. It is confirmed that the W-1.5%ZrO₂ alloy shows a smaller change in hardness than the pure tungsten after being irradiated. From the above results, we conclude that the addition of ZrO₂ into tungsten can significantly reduce the accumulation of irradiated defects and improve the irradiation resistance behaviors of the tungsten materials.

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Structural evolution and molecular dissociation of H₂S under high pressures

Wen-Ji Shen(沈文吉), Tian-Xiao Liang(梁天笑), Zhao Liu(刘召), Xin Wang(王鑫), De-Fang Duan(段德芳), Hong-Yu Yu(于洪雨), and Tian Cui(崔田)

Chin. Phys. B, 2022, 31 (7): 076102. DOI: 10.1088/1674-1056/ac5980

Abstract （365）

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Solid H$_{2}$S as the precursor for H$_{3}$S with incredible superconducting properties under high pressure, has recently attracted extensive attention. Here in this work, we propose two new phases of H$_{2}$S with $P$4$_{2}/n$ and $I$4$_{1}/a$ lattice symmetries in a pressure range of 0 GPa-30 GPa through first-principles structural searches, which complement the phase transition sequence. Further an $ab initio$ molecular dynamics simulation confirms that the molecular phase $P2/c$ of H$_{2}$S is gradually dissociated with the pressure increasing and reconstructs into a new $P$2$_{1}/m$ structure at 160 GPa, exhibiting the superconductivity with $T_{\rm c}$ of 82.5 K. Our results may provide a guidance for the theoretical study of low-temperature superconducting phase of H$_{2}$S.

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Surface electron doping induced double gap opening in T_d-WTe₂

Qi-Yuan Li(李启远), Yang-Yang Lv(吕洋洋), Yong-Jie Xu(徐永杰), Li Zhu(朱立), Wei-Min Zhao(赵伟民), Yanbin Chen(陈延彬), and Shao-Chun Li(李绍春)

Chin. Phys. B, 2022, 31 (6): 066802. DOI: 10.1088/1674-1056/ac632e

Abstract （363）

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By using scanning tunneling microscopy, we investigated the electronic evolution of T_d-WTe₂ via in-situ surface alkali K atoms deposition. The T_d-WTe₂ surface is electron doped upon K deposition, and as the K coverage increases, two gaps are sequentially opened near Fermi energy, which probably indicates that two phase transitions concomitantly occur during electron doping. The two gaps both show a dome-like dependence on the K coverage. While the bigger gap shows no prominent dependence on the magnetic field, the smaller one can be well suppressed and thus possibly corresponds to the superconducting transition. This work indicates that T_d-WTe₂ exhibits rich quantum states closely related to the carrier concentration.

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Gate tunable Rashba spin-orbit coupling at CaZrO₃/SrTiO₃ heterointerface

Wei-Min Jiang(姜伟民), Qiang Zhao(赵强), Jing-Zhuo Ling(凌靖卓), Ting-Na Shao(邵婷娜), Zi-Tao Zhang(张子涛), Ming-Rui Liu(刘明睿), Chun-Li Yao(姚春丽), Yu-Jie Qiao(乔宇杰), Mei-Hui Chen(陈美慧), Xing-Yu Chen(陈星宇), Rui-Fen Dou(窦瑞芬), Chang-Min Xiong(熊昌民), and Jia-Cai Nie(聂家财)

Chin. Phys. B, 2022, 31 (6): 066801. DOI: 10.1088/1674-1056/ac5396

Abstract （357）

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High mobility quasi two-dimensional electron gas (2DEG) found at the CaZrO₃/SrTiO₃ nonpolar heterointerface is attractive and provides a platform for the development of functional devices and nanoelectronics. Here we report that the carrier density and mobility at low temperature can be tuned by gate voltage at the CaZrO₃/SrTiO₃ interface. Furthermore, the magnitude of Rashba spin-orbit interaction can be modulated and increases with the gate voltage. Remarkably, the diffusion constant and the spin-orbit relaxation time can be strongly tuned by gate voltage. The diffusion constant increases by a factor of ～ 19.98 and the relaxation time is reduced by a factor of over three orders of magnitude while the gate voltage is swept from -50 V to 100 V. These findings not only lay a foundation for further understanding the underlying mechanism of Rashba spin-orbit coupling, but also have great significance in developing various oxide functional devices.

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First-principles study of a new BP₂ two-dimensional material

Zhizheng Gu(顾志政), Shuang Yu(于爽), Zhirong Xu(徐知荣), Qi Wang(王琪), Tianxiang Duan(段天祥), Xinxin Wang(王鑫鑫), Shijie Liu(刘世杰), Hui Wang(王辉), and Hui Du(杜慧)

Chin. Phys. B, 2022, 31 (8): 086107. DOI: 10.1088/1674-1056/ac5a40

Abstract （353）

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Two-dimensional materials have a wide range of applications in many aspects due to their unique properties. Here we carry out a detailed structural search and design of the BP₂ using the first principles method, and find a new PMM2 sheet. The analysis of the phonon dispersive curves shows that the 2D PMM2 is dynamic stable. The study of molecular dynamics shows that the 2D PMM2 can be stable under high temperature, even at 600 K. Most importantly, when a suitable strain is applied, the structure can exhibit other electronic properties such as direct band gap semiconductor. In addition, the small strain can tune the band gap value of the PMM2 structure to around 1.4 eV, which is very close to the ideal band gap of solar materials. Therefore, the 2D PMM2 may have potential applications in the field of photovoltaic materials.

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Tunable anharmonicity versus high-performance thermoelectrics and permeation in multilayer (GaN)_1-x(ZnO)_x

Hanpu Liang(梁汉普) and Yifeng Duan(段益峰)

Chin. Phys. B, 2022, 31 (7): 076301. DOI: 10.1088/1674-1056/ac5c38

Abstract （349）

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Nonisovalent (GaN)$_{1-x}$(ZnO)$_x$ alloys are more technologically promising than their binary counterparts because of the abruptly reduced band gap. Unfortunately, the lack of two-dimensional (2D) configurations as well as complete stoichiometries hinders to further explore the thermal transport, thermoelectrics, and adsorption/permeation. We identify that multilayer (GaN)$_{1-x}$(ZnO)$_x$ stabilize as wurtzite-like $Pm$-(GaN)$_3$(ZnO)$_1$, $Pmc2_1$-(GaN)$_1$(ZnO)$_1$, $P3m1$-(GaN)$_1$(ZnO)$_2$, and haeckelite $C2/m$-(GaN)$_1$(ZnO)$_3$ via structural searches. $P3m1$-(GaN)$_1$(ZnO)$_2$ shares the excellent thermoelectrics with the figure of merit $ZT$ as high as 3.08 at 900 K for the p-type doping due to the ultralow lattice thermal conductivity, which mainly arises from the strong anharmonicity by the interlayer asymmetrical charge distributions. The $p$-$d$ coupling is prohibited from the group theory in $C2/m$-(GaN)$_1$(ZnO)$_3$, which thereby results in the anomalous band structure versus ZnO composition. To unveil the adsorption/permeation of H$^+$, Na$^+$, and OH$^-$ ions in $AA$-stacking configurations, the potential wells and barriers are explored from the Coulomb interaction and the ionic size. Our work is helpful in experimental fabrication of novel optoelectronic and thermoelectric devices by 2D (GaN)$_{1-x}$(ZnO)$_x$ alloys.

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Strengthening and softening in gradient nanotwinned FCC metallic multilayers

Yuanyuan Tian(田圆圆), Gangjie Luo(罗港杰), Qihong Fang(方棋洪), Jia Li(李甲), and Jing Peng(彭静)

Chin. Phys. B, 2022, 31 (6): 066204. DOI: 10.1088/1674-1056/ac4cc6

Abstract （348）

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Plastic-deformation behaviors of gradient nanotwinned (GNT) metallic multilayers are investigated in nanoscale via molecular dynamics simulation. The evolution law of deformation behaviors of GNT metallic multilayers with different stacking fault energies (SFEs) during nanoindentation is revealed. The deformation behavior transforms from the dislocation dynamics to the twinning/detwinning in the GNT Ag, Cu, to Al with SFE increasing. In addition, it is found that the GNT Ag and GNT Cu strengthen in the case of a larger twin gradient based on more significant twin boundary (TB) strengthening and dislocation strengthening, while the GNT Al softens due to more TB migration and dislocation nucleation from TB at a larger twin gradient. The softening mechanism is further analyzed theoretically. These results not only provide an atomic insight into the plastic-deformation behaviors of certain GNT metallic multilayers with different SFEs, but also give a guideline to design the GNT metallic multilayers with required mechanical properties.

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Synthesis of hexagonal boron nitride films by dual temperature zone low-pressure chemical vapor deposition

Zhi-Fu Zhu(朱志甫), Shao-Tang Wang(王少堂), Ji-Jun Zou(邹继军), He Huang(黄河), Zhi-Jia Sun(孙志嘉), Qing-Lei Xiu(修青磊), Zhong-Ming Zhang(张忠铭), Xiu-Ping Yue(岳秀萍), Yang Zhang(张洋), Jin-Hui Qu(瞿金辉), and Yong Gan(甘勇)

Chin. Phys. B, 2022, 31 (8): 086103. DOI: 10.1088/1674-1056/ac657d

Abstract （347）

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Hexagonal boron nitride (h-BN) films are synthesized by dual temperature zone low-pressure chemical vapor deposition (LPCVD) through using a single ammonia borane precursor on non-catalytic c-plane Al₂O₃ substrates. The grown films are confirmed to be h-BN films by various characterization methods. Meanwhile, the growth rates and crystal quality of h-BN films at different positions in the dual temperature zone are studied. It is found that the growth rates and crystal quality of the h-BN films at different positions on the substrate are significantly different. The growth rates of the h-BN thin films show their decreasing trends with the rearward position, while the crystal quality is improved. This work provides an experimental basis for the preparation of large area wafer thick h-BN films by LPCVD.

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Influence of particle size on the breaking of aluminum particle shells

Tian-Yi Wang(王天一), Zheng-Qing Zhou(周正青), Jian-Ping Peng(彭剑平),Yu-Kun Gao(高玉坤), and Ying-Hua Zhang(张英华)

Chin. Phys. B, 2022, 31 (7): 076107. DOI: 10.1088/1674-1056/ac5615

Abstract （335）

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Rupturing the alumina shell (shell-breaking) is a prerequisite for releasing energy from aluminum powder. Thermal stress overload in a high-temperature environment is an important factor in the rupture of the alumina shell. COMSOL Multiphysics was used to simulate and analyze the shell-breaking response of micron-scale aluminum particles with different particle sizes at 650 ℃ in vacuum. The simulation results show that the thermal stability time and shell-breaking response time of 10 μm-100 μm aluminum particles are 0.15 μs-11.44 μs and 0.08 μs-3.94 μs, respectively. They also reveal the direct causes of shell breaking for aluminum particles with different particle sizes. When the particle size is less than 80 μm, the shell-breaking response is a direct result of compressive stress overload. When the particle size is between 80 μm and 100 μm, the shell-breaking response is a direct result of tensile stress overload. This article provides useful guidance for research into the energy release of aluminum powder.

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High-pressure new phases of V-N compounds

Xu-Han Shi(时旭含), Zhi-Hui Li(李志慧), Yuanyuan Liu(刘媛媛), Yuanyuan Wang(王元元), Ran Liu(刘冉), Kuo Hu(胡阔), and Zhen Yao(姚震)

Chin. Phys. B, 2023, 32 (5): 056103. DOI: 10.1088/1674-1056/acbc6d

Abstract （330）

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The high-pressure diagram of V-N compounds is enriched by proposed seven new stable high-pressure phases. The $P$-1-VN$_{4}$ with the armchair N-rich structure may be quenched to ambient conditions. The formed N-N covalent bond plays an important role for the structural stability of N-chain. The charge transfer results in a V-N ionic bond interaction, which further improves the stability of N-chain structure. The $P$-1-VN$_{4}$, $P4mnc$-VN$_{8}$, and $Immm$-VN$_{10}$ with the outstanding detonation properties have potential application in explosive field.

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Vacuum current-carrying tribological behavior of MoS₂-Ti films with different conductivities

Lu-Lu Pei(裴露露), Peng-Fei Ju(鞠鹏飞), Li Ji(吉利), Hong-Xuan Li(李红轩),Xiao-Hong Liu(刘晓红), Hui-Di Zhou(周惠娣), and Jian-Min Chen(陈建敏)

Chin. Phys. B, 2022, 31 (6): 066201. DOI: 10.1088/1674-1056/ac4f5a

Abstract （326）

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Current-carrying sliding is widely applied in aerospace equipment, but it is limited by the poor lubricity of the present materials and the unclear tribological mechanism. This study demonstrated the potential of MoS₂-based materials with excellent lubricity as space sliding electrical contact materials by doping Ti to improve its conductivity. The tribological behavior of MoS₂-Ti films under current-carrying sliding in vacuum was studied by establishing a simulation evaluating device. Moreover, the noncurrent-carrying sliding and static current-carrying experiments in vacuum were carried out for comparison to understand the tribological mechanism. In addition to mechanical wear, the current-induced arc erosion and thermal effect take important roles in accelerating the wear. Arc erosion is caused by the accumulation of electric charge, which is related to the conductivity of the film. While the current-thermal effect softens the film, causing strong adhesive wear, and good conductivity and the large contact area are beneficial for minimizing the thermal effect. So the moderate hardness and good conductivity of MoS₂-Ti film contribute to its excellent current-carrying tribological behavior in vacuum, showing a significant advantage compared with the traditional ones.

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Porous AlN films grown on C-face SiC by hydride vapor phase epitaxy

Jiafan Chen(陈家凡), Jun Huang(黄俊), Didi Li(李迪迪), and Ke Xu(徐科)

Chin. Phys. B, 2022, 31 (7): 076802. DOI: 10.1088/1674-1056/ac597e

Abstract （325）

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We report the growth of porous AlN films on C-face SiC substrates by hydride vapor phase epitaxy (HVPE). The influences of growth condition on surface morphology, residual strain and crystalline quality of AlN films have been investigated. With the increase of the V/III ratio, the growth mode of AlN grown on C-face 6H-SiC substrates changes from step-flow to pit-hole morphology. Atomic force microscopy (AFM), scanning electron microscopy (SEM) and Raman analysis show that cracks appear due to tensile stress in the films with the lowest V/III ratio and the highest V/III ratio with a thickness of about 3 μm. In contrast, under the medium V/III ratio growth condition, the porous film can be obtained. Even when the thickness of the porous AlN film is further increased to 8 μm, the film remains porous and crack-free, and the crystal quality is improved.

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Theoretical and experimental study of phase optimization of tapping mode atomic force microscope

Zheng Wei(魏征), An-Jie Peng(彭安杰), Feng-Jiao Bin(宾凤姣), Ya-Xin Chen(陈亚鑫), and Rui Guan(关睿)

Chin. Phys. B, 2022, 31 (7): 076801. DOI: 10.1088/1674-1056/ac4a6d

Abstract （324）

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Phase image in tapping-mode atomic force microscope (TM-AFM) results from various dissipations in a microcantilever system. The phases mainly reflect the tip-sample contact dissipations which allow the nanoscale characteristics to be distinguished from each other. In this work, two factors affecting the phase and phase contrast are analyzed. It is concluded from the theoretical and experimental results that the phases and phase contrasts in the TM-AFM are related to the excitation frequency and energy dissipation of the system. For a two-component blend, it is theoretically and experimentally proven that there exists an optimal excitation frequency for maximizing the phase contrast. Therefore, selecting the optimal excitation frequency can potentially improve the phase contrast results. In addition, only the key dissipation between the tip and sample is found to accurately reflect the sample properties. Meanwhile, the background dissipation can potentially reduce the contrasts of the phase images and even mask or distort the effective information in the phase images. In order to address the aforementioned issues, a self-excited method is adopted in this study in order to eliminate the effects of the background dissipation on the phases. Subsequently, the real phase information of the samples is successfully obtained. It is shown in this study that the eliminating of the background dissipation can effectively improve the phase contrast results and the real phase information of the samples is accurately reflected. These results are of great significance in optimizing the phases of two-component samples and multi-component samples in atomic force microscope.

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Heterogeneous integration of GaSb layer on (100) Si substrate by ion-slicing technique

Ren-Jie Liu(刘仁杰), Jia-Jie Lin(林家杰), Zheng-Hao Shen(沈正皓), Jia-Liang Sun(孙嘉良), Tian-Gui You(游天桂), Jin Li(李进), Min Liao(廖敏), and Yi-Chun Zhou(周益春)

Chin. Phys. B, 2022, 31 (7): 076103. DOI: 10.1088/1674-1056/ac5605

Abstract （323）

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Integration of the high-quality GaSb layer on an Si substrate is significant to improve the GaSb application in optoelectronic integration. In this work, a suitable ion implantation fluence of 5×10¹⁶-cm^-2 H ions for GaSb layer transfer is confirmed. Combining the strain change and the defect evolution, the blistering and exfoliation processes of GaSb during annealing is revealed in detail. With the direct wafer bonding, the GaSb layer is successfully transferred onto a (100) Si substrate covered by 500-nm thickness thermal oxide SiO₂ layer. After being annealed at 200 ℃, the GaSb layer shows high crystalline quality with only 77 arcsec for the full width at half maximum (FWHM) of the x-ray rocking curve (XRC).

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Structure, phase evolution and properties of Ta films deposited using hybrid high-power pulsed and DC magnetron co-sputtering

Min Huang(黄敏), Yan-Song Liu(刘艳松), Zhi-Bing He(何智兵), and Yong Yi(易勇)

Chin. Phys. B, 2022, 31 (6): 066101. DOI: 10.1088/1674-1056/ac43a9

Abstract （322）

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Crystalline phase and microstructure control are critical for obtaining desired properties of Ta films deposited by magnetron sputtering. Structure, phase evolution and properties of Ta films deposited by using hybrid high power impulse magnetron sputtering (HiPIMS) and direct current magnetron sputtering (DCMS) under different fractions of DCMS power were investigated, where Ta ion to Ta neutral ratios of the deposition flux were changed. The results revealed that the number of Ta ions arriving on the substrate/growing film plays an important role in structure and phase evolution of Ta films. It can effectively avoid the unstable arc discharge under low pressure and show a higher deposition rate by combining HiPIMS and DCMS compared with only HiPIMS. Meanwhile, the high hardness α -Ta films can be directly deposited by hybrid co-sputtering compared to those prepared by DCMS. In the co-sputtering technology, pure α -Ta phase films with extremely fine, dense and uniform crystal grains were obtained, which showed smooth surface roughness (3.22 nm), low resistivity (38.98 μΩ · cm) and abnormal high hardness (17.64 GPa).

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Molecular dynamics simulation of interaction between nanorod and phospholipid molecules bilayer

Xin Wang(王鑫), Xiang-Qin Li(李香琴), Tian-Qing Liu(刘天庆), Li-Dan Zhao(赵丽丹), Ke-Dong Song(宋克东), and Dan Ge(葛丹)

Chin. Phys. B, 2023, 32 (1): 016201. DOI: 10.1088/1674-1056/ac6ed8

Abstract （320）

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Natural and artificially prepared nanorods' surfaces have proved to have good bactericidal effect and self-cleaning property. In order to investigate whether nanorods can kill the enveloped virus, like destroying bacterial cell, we study the interaction between nanorods and virus envelope by establishing the models of nanorods with different sizes as well as the planar membrane and vesicle under the Dry Martini force field of molecular dynamics simulation. The results show that owing to the van der Waals attraction between nanorods and the tail hydrocarbon chain groups of phospholipid molecules, the phospholipid molecules on virus envelope are adsorbed to nanorods on a large scale. This process will increase the surface tension of lipid membrane and reduce the order of lipid molecules, resulting in irreparable damage to planar lipid membrane. Nanorods with different diameters have different effects on vesicle envelope, the larger the diameter of nanorod, the weaker the van der Waals effect on the unit cross-sectional area is and the smaller the degree of vesicle deformation. There is synergy between the nanorods in the nanorod array, which can enhance the speed and scale of lipid adsorption. The vesicle adsorbed in the array are difficult to desorb, and even if desorbed, vesicle will be seriously damaged. The deformation rate of the vesicle adsorbed in the nanorod array exceeds 100%, implying that the nanorod array has a strong destructive effect on the vesicle. This preliminarily proves the feasibility of nanorod array on a surface against enveloped virus, and provides a reference for the design of corresponding nanorods surface.

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