Top downloaded

Published in last 1 year | In last 2 years| In last 3 years| All| Most downloaded in recent month| Most downloaded in recent year

Most downloaded in recent month

Please wait a minute...


For selected: Download citations EndNote Ris BibTeX Toggle thumbnails

Select

Generation of valley pump currents in silicene John Tombe Jada Marcellino, Mei-Juan Wang(王美娟), Sa-Ke Wang(汪萨克) Chin. Phys. B, 2019, 28 (1): 017204.   DOI: 10.1088/1674-1056/28/1/017204 Abstract （197857）   HTML    PDF （433KB）（195881）       Knowledge map    We propose a workable scheme for generating a bulk valley pump current in a silicene-based device which consists of two pumping regions characterized by time-dependent strain and staggered potentials, respectively. In a one-dimension model, we show that a pure valley current can be generated, in which the two valley currents have the same magnitude but flow in opposite directions. Besides, the pumped valley current is quantized and maximized when the Fermi energy of the system locates in the bandgap opened by the two pumping potentials. Furthermore, the valley current can be finely controlled by tuning the device parameters. Our results are useful for the development of valleytronic devices based on two-dimensional materials.

Select

Spin and valley filter in strain engineered silicene Wang Sa-Ke (汪萨克), Wang Jun (汪军) Chin. Phys. B, 2015, 24 (3): 037202.   DOI: 10.1088/1674-1056/24/3/037202 Abstract （182532）   HTML    PDF （643KB）（181402）       Knowledge map    The realization of a perfect spin or valley filtering effect in two-dimensional graphene-like materials is one of the fundamental objectives in spintronics and valleytronics. For this purpose, we study spin- and valley-dependent transport in a silicene system with spatially alternative strains. It is found that due to the valley-opposite gauge field induced by the strain, the strained silicene with a superlattice structure exhibits an angle-resolved valley and spin filtering effect when the spin-orbit interaction is considered. When the interaction that breaks the time reversal symmetry is introduced, such as the spin or valley dependent staggered magnetization, the system is shown to be a perfect spin and valley half metal in which only one spin and valley species is allowed to transport. Our findings are helpful to design both spintronic and valleytronic devices based on silicene.

Select

Spin and valley half metal induced by staggered potential and magnetization in silicene Wang Sa-Ke (汪萨克), Tian Hong-Yu (田宏玉), Yang Yong-Hong (杨永宏), Wang Jun (汪军) Chin. Phys. B, 2014, 23 (1): 017203.   DOI: 10.1088/1674-1056/23/1/017203 Abstract （172943）      PDF （639KB）（173723）       Knowledge map    We investigate the electron transport in silicene with both staggered electric potential and magnetization; the latter comes from the magnetic proximity effect by depositing silicene on a magnetic insulator. It is shown that the silicene could be a spin and valley half metal under appropriate parameters when the spin–orbit interaction is considered; further, the filtered spin and valley could be controlled by modulating the staggered potential or magnetization. It is also found that in the spin-valve structure of silicene, not only can the antiparallel magnetization configuration significantly reduce the valve-structure conductance, but the reversing staggered electric potential can cause a high-performance magnetoresistance due to the spin and valley blocking effects. Our findings show that the silicene might be an ideal basis for the spin and valley filter analyzer devices.

Select

The influence of hole shape on enhancing transmission through subwavelength hole arrays Sun Mei (孙梅), Liu Rong-Juan (刘荣鹃), Li Zhi-Yuan (李志远), Cheng Bing-Ying (程丙英), Zhang Dao-Zhong (张道中), Yang Hai-Fang (杨海方), Jin Ai-Zi (金爱子) Chinese Physics, 2006, 15 (7): 1591-1594.   DOI: 10.1088/1009-1963/15/7/036 Abstract （1484）      PDF （1054KB）（669）       Knowledge map    The extraordinary light transmission through a 200-nm thick gold film when passing through different subwavelength hole arrays is observed experimentally. The sample is fabricated by electron beam lithography and reactive ion etching system. A comparison between light transmissions shows that the hole shape changing from rectangular to diamond strongly affects the transmission intensity although both structures possess the same lattice constant of 600 nm. Moreover, the position of the transmission maximum undergoes a spectral red-shift of about 63 nm. Numerical simulations by using a transfer matrix method reproduce the observed transmission spectrum quite well.

Select

Exponential--fraction trial function method to the 5th-order mKdV equation Li Ya-Zhou(李亚洲), Feng Wei-Gui(冯维贵), Li Kai-Ming(李开明), and Lin Chang(林长) Chinese Physics, 2007, 16 (9): 2510-2513.   DOI: 10.1088/1009-1963/16/9/004 Abstract （1348）      PDF （269KB）（676）       Knowledge map    This paper obtains some solutions of the 5th-order mKdV equation by using the exponential--fraction trial function method, such as solitary wave solutions, shock wave solutions and the hopping wave solutions. It successfully shows that this method may be valid for solving other nonlinear partial differential equations.

Select

Layered kagome compound Na2Ni3S4 with topological flat band Junyao Ye(叶君耀), Yihao Lin(林益浩), Haozhe Wang(王浩哲), Zhida Song(宋志达), Ji Feng(冯济), Weiwei Xie(谢韦伟), and Shuang Jia(贾爽) Chin. Phys. B, 2024, 33 (5): 057103.   DOI: 10.1088/1674-1056/ad3431 Abstract （288）   HTML （14）    PDF （2643KB）（266）       Knowledge map    We report structural and electronic properties of Na$_2$Ni$_3$S$_4$, a quasi-two-dimensional compound composed of alternating layers of [Ni$_3$S$_4$]$^{2-}$ and Na$^{+}$. The compound features a remarkable Ni-based kagome lattice with a square planar configuration of four surrounding S atoms for each Ni atom. Magnetization and electrical measurements reveal a weak paramagnetic insulator with a gap of about 0.5 eV.Our band structure calculation highlights a set of topological flat bands of the kagome lattice derived from the rotated d$_{xz}$-orbital with $C_\mathrm{3}$ + $T$ symmetry in the presence of crystal-field splitting.

Select

In vivo hyperthermia effect induced by high-intensity pulsed ultrasound Cui Wei-Cheng(崔炜程), Tu Juan(屠娟), Hwang Joo-Ha, Li Qian (李倩), Fan Ting-Bo(范庭波), Zhang Dong(章东), Chen Jing-Hai(陈静海), and Chen Wei-Zhong(陈伟中) Chin. Phys. B, 2012, 21 (7): 074301.   DOI: 10.1088/1674-1056/21/7/074301 Abstract （1476）      PDF （594KB）（802）       Knowledge map    Hyperthermia effects (39--44 ℃) induced by pulsed high-intensity focused ultrasound (HIFU) have been regarded as a promising therapeutic tool for boosting immune responses or enhancing drug delivery into solid tumor. However, previous studies also reported that the cell death occurs when cells are maintained at 43 ℃ for more than 20 minutes. The aim of this study is to investigate thermal responses inside in vivo rabbit auricular veins exposed to pulsed HIFU (1.17 MHz, 5300 W/cm2, with relatively low-duty ratios (0.2%--4.3%). The results show that: (1) with constant pulse repetition frequency (PRF) (e.g., 1 Hz), the thermal responses inside the vessel will increase with the increasing duty ratio; (2) a temperature elevation to 43 ℃ can be identified at the duty ratio of 4.3%; (3) with constant duty ratios, the change of PRF will not significantly affect the temperature measurement in the vessel; (4) as the duty ratios lower than 4.3%, the presence of microbubbles will not significantly enhance the thermal responses in the vessel, but will facilitate HIFU-induced inertial cavitation events.

Select

Controlling the dynamic behavior of decentralized cluster through centralized approaches Daming Yuan(袁大明), Peilong Wang(王培龙), Peng Wang(王鹏), Xingyu Ma(马星宇), Chuyun Wang(汪楚云), Jing Wang(王璟), Huaicheng Chen(陈怀城), Gao Wang(王高), and Fangfu Ye(叶方富) Chin. Phys. B, 2024, 33 (6): 060702.   DOI: 10.1088/1674-1056/ad3dd0 Abstract （144）      PDF （3679KB）（104）       Knowledge map    How to control the dynamic behavior of large-scale artificial active matter is a critical concern in experimental research on soft matter, particularly regarding the emergence of collective behaviors and the formation of group patterns. Centralized systems excel in precise control over individual behavior within a group, ensuring high accuracy and controllability in task execution. Nevertheless, their sensitivity to group size may limit their adaptability to diverse tasks. In contrast, decentralized systems empower individuals with autonomous decision-making, enhancing adaptability and system robustness. Yet, this flexibility comes at the cost of reduced accuracy and efficiency in task execution. In this work, we present a unique method for regulating the centralized dynamic behavior of self-organizing clusters based on environmental interactions. Within this environment-coupled robot system, each robot possesses similar dynamic characteristics, and their internal programs are entirely identical. However, their behaviors can be guided by the centralized control of the environment, facilitating the accomplishment of diverse cluster tasks. This approach aims to balance the accuracy and flexibility of centralized control with the robustness and task adaptability of decentralized control. The proactive regulation of dynamic behavioral characteristics in active matter groups, demonstrated in this work through environmental interactions, holds the potential to introduce a novel technological approach and provide experimental references for studying the dynamic behavior control of large-scale artificial active matter systems.

Select

Influence of N+ implantation on structure, morphology, and corrosion behavior of Al in NaCl solution Hadi Savaloni, Rezvan Karami, Helma Sadat Bahari, Fateme Abdi Chin. Phys. B, 2020, 29 (5): 058102.   DOI: 10.1088/1674-1056/ab7d97 Abstract （523）   HTML    PDF （3471KB）（299）       Knowledge map    Structural and morphological changes as well as corrosion behavior of N+ implanted Al in 0.6 M NaCl solution as function of N+ fluence are investigated. The x-ray diffraction results confirmed AlN formation. The atomic force microscope (AFM) images showed larger grains on the surface of Al with increasing N+ fluence. This can be due to the increased number of impacts of N+ with Al atoms and energy conversion to heat, which increases the diffusion rate of the incident ions in the target. Hence, the number of the grain boundaries is reduced, resulting in corrosion resistance enhancement. Electrochemical impedance spectroscopy (EIS) and polarization results showed the increase of corrosion resistance of Al with increasing N+ fluence. EIS data was used to simulate equivalent electric circuits (EC) for the samples. Strong dependence of the surface morphology on the EC elements was observed. The scanning electron microscope (SEM) analysis of the samples after corrosion test also showed that the surfaces of the implanted Al samples remain more intact relative to the untreated Al sample, consistent with the EIS and polarization results.

Select

Nonreciprocal transport in the superconducting state of the chiral crystal NbGe2 Yonglai Liu(刘永来), Xitong Xu(许锡童), Miao He(何苗), Haitian Zhao(赵海天), Qingqi Zeng(曾庆祺), Xingyu Yang(杨星宇), Youming Zou(邹优鸣), Haifeng Du(杜海峰), and Zhe Qu(屈哲) Chin. Phys. B, 2024, 33 (5): 057402.   DOI: 10.1088/1674-1056/ad334b Abstract （154）   HTML （11）    PDF （2451KB）（139）       Knowledge map    Due to the lack of inversion, mirror or other roto-inversion symmetries, chiral crystals possess a well-defined handedness which, when combined with time-reversal symmetry breaking from the application of magnetic fields, can give rise to directional dichroism of the electrical transport phenomena via the magnetochiral anisotropy. In this study, we investigate the nonreciprocal magneto-transport in microdevices of NbGe$_{2}$, a superconductor with structural chirality. A giant nonreciprocal signal from vortex motions is observed during the superconducting transition, with the ratio of nonreciprocal resistance to the normal resistance ${\gamma}$ reaching 6$\times10^{5}$~T$^{-1}$$\cdot$A$^{-1}$. Interestingly, the intensity can be adjusted and even sign-reversed by varying the current, the temperature, and the crystalline orientation. Our findings illustrate intricate vortex dynamics and offer ways of manipulation on the rectification effect in superconductors with structural chirality.

Select

Cold atom clocks and their applications in precision measurements Shao-Yang Dai(戴少阳), Fa-Song Zheng(郑发松), Kun Liu(刘昆), Wei-Liang Chen(陈伟亮), Yi-Ge Lin(林弋戈), Tian-Chu Li(李天初), and Fang Fang(房芳) Chin. Phys. B, 2021, 30 (1): 013701.   DOI: 10.1088/1674-1056/abbbee Abstract （629）   HTML （11）    PDF （3844KB）（649）       Knowledge map    Cold atom clocks have made remarkable progresses in the last two decades and played critical roles in precision measurements. Primary Cs fountain frequency standards have achieved a total uncertainty of a few parts in 1016, and the best optical clock has reached a type B uncertainty below 10-18. Besides applications in the metrology, navigation, etc., ultra-stable and ultra-accurate atomic clocks have also become powerful tools in the basic scientific investigations. In this paper, we focus on the recent developments in the high-performance cold atomic clocks which can be used as frequency standards to calibrate atomic time scales. The basic principles, performances, and limitations of fountain clocks and optical clocks based on signal trapped ion or neutral atoms are summarized. Their applications in metrology and other areas are briefly introduced.

Select

Estimation of cancer cell migration in biomimetic random/oriented collagen fiber microenvironments Jingru Yao(姚静如), Guoqiang Li(李国强), Xiyao Yao(姚喜耀), Lianjie Zhou(周连杰), Zhikai Ye(叶志凯), Yanping Liu(刘艳平), Dongtian Zheng(郑栋天), Ting Tang(唐婷), Kena Song(宋克纳), Guo Chen(陈果), and Liyu Liu(刘雳宇) Chin. Phys. B, 2024, 33 (5): 058706.   DOI: 10.1088/1674-1056/ad334c Abstract （99）   HTML （4）    PDF （3033KB）（117）       Knowledge map    Increasing data indicate that cancer cell migration is regulated by extracellular matrixes and their surrounding biochemical microenvironment, playing a crucial role in pathological processes such as tumor invasion and metastasis. However, conventional two-dimensional cell culture and animal models have limitations in studying the influence of tumor microenvironment on cancer cell migration. Fortunately, the further development of microfluidic technology has provided solutions for the study of such questions. We utilize microfluidic chip to build a random collagen fiber microenvironment (RFM) model and an oriented collagen fiber microenvironment (OFM) model that resemble early stage and late stage breast cancer microenvironments, respectively. By combining cell culture, biochemical concentration gradient construction, and microscopic imaging techniques, we investigate the impact of different collagen fiber biochemical microenvironments on the migration of breast cancer MDA-MB-231-RFP cells. The results show that MDA-MB-231-RFP cells migrate further in the OFM model compared to the RFM model, with significant differences observed. Furthermore, we establish concentration gradients of the anticancer drug paclitaxel in both the RFM and OFM models and find that paclitaxel significantly inhibits the migration of MDA-MB-231-RFP cells in the RFM model, with stronger inhibition on the high concentration side compared to the low concentration side. However, the inhibitory effect of paclitaxel on the migration of MDA-MB-231-RFP cells in the OFM model is weak. These findings suggest that the oriented collagen fiber microenvironment resembling the late-stage tumor microenvironment is more favorable for cancer cell migration and that the effectiveness of anticancer drugs is diminished. The RFM and OFM models constructed in this study not only provide a platform for studying the mechanism of cancer development, but also serve as a tool for the initial measurement of drug screening.

Select

Preparation of nonclassical states and measurement of the Wigner function for the collective motion of N trapped ions Zheng Shi-Biao (郑仕标) Chinese Physics, 2004, 13 (11): 1862-1865.   DOI: 10.1088/1009-1963/13/11/017 Abstract （1310）      PDF （145KB）（523）       Knowledge map    We propose a scheme for generating nonclassical states for the centre-of-mass vibrational mode of N trapped ions, including superpositions of several coherent states on a circle and Fock states. In the scheme N trapped ions are driven by a laser beam tuned to the carrier. The scheme also provides a new prospect for laser cooling. The scheme can be used to measure the Wigner function of the collective vibrational mode.

Select

Relationship between disorder, magnetism and band topology in Mn(Sb1-xBix)2Te4 single crystals Ming Xi(席明) and Hechang Lei(雷和畅) Chin. Phys. B, 2024, 33 (6): 067503.   DOI: 10.1088/1674-1056/ad3dd8 Abstract （73）      PDF （919KB）（75）       Knowledge map    We investigate the evolution of magnetic properties as well as the content and distribution of Mn for Mn(Sb$_{1-x}$Bi$_{x}$)$_{2}$Te$_{4}$ single crystals grown by large-temperature-gradient chemical vapor transport method. It is found that the ferromagnetic MnSb$_{2}$Te$_{4}$ changes to antiferromagnetism with Bi doping when $x \ge 0.25$. Further analysis implies that the occupations of Mn ions at Sb/Bi site Mn$_{\rm Sb/Bi}$ and Mn site Mn$_{\rm Mn}$ have a strong influence on the magnetic ground states of these systems. With the decrease of Mn$_{\rm Mn}$ and increase of Mn$_{\rm Sb/Bi}$, the system will favor the ferromagnetic ground state. In addition, the rapid decrease of $T_{\rm C/N}$ with increasing Bi content when $x \le 0.25$ and the insensitivity of $T_{\rm N}$ to $x$ when $x > 0.25$ suggest that the main magnetic interaction may change from the Ruderman-Kittel-Kasuya-Yosida type at low Bi doping region to the van-Vleck type in high Bi doped samples.

Select

Field induced Chern insulating states in twisted monolayer-bilayer graphene Zhengwen Wang(王政文), Yingzhuo Han(韩英卓), Kenji Watanabe, Takashi Taniguchi, Yuhang Jiang(姜宇航), and Jinhai Mao(毛金海) Chin. Phys. B, 2024, 33 (6): 067301.   DOI: 10.1088/1674-1056/ad3b8a Abstract （90）      PDF （1262KB）（71）       Knowledge map    Unraveling the mechanism underlying topological phases, notably the Chern insulators (ChIs) in strong correlated systems at the microscopy scale, has captivated significant research interest. Nonetheless, ChIs harboring topological information have not always manifested themselves, owing to the constraints imposed by displacement fields in certain experimental configurations. In this study, we employ density-tuned scanning tunneling microscopy (DT-STM) to investigate the ChIs in twisted monolayer-bilayer graphene (tMBG). At zero magnetic field, we observe correlated metallic states. While under a magnetic field, a metal-insulator transition happens and an integer ChI is formed emanating from the filling index $ s = 3$ with a Chern number $C = 1$. Our results underscore the pivotal role of magnetic fields as a powerful probe for elucidating topological phases in twisted Van der Waals heterostructures.

Select

Photon counts modulation in optical time domain reflectometry Wang Xiao-Bo(王晓波), Wang Jing-Jing(王晶晶), Zhang Guo-Feng(张国锋), Xiao Lian-Tuan(肖连团), and Jia Suo-Tang(贾锁堂) Chin. Phys. B, 2011, 20 (6): 064204.   DOI: 10.1088/1674-1056/20/6/064204 Abstract （1439）      PDF （523KB）（798）       Knowledge map    The quantum fluctuation of photon counting limits the field application of optical time domain reflection. A method of photon counts modulation optics time domain reflection with single photon detection at 1.55 μm is presented. The influence of quantum fluctuation can be effectively controlled by demodulation technology since quantum fluctuation shows a uniform distribution in the frequency domain. Combined with the changing of the integration time of the lock-in amplifier, the signal to noise ratio is significantly enhanced. Accordingly the signal to noise improvement ratio reaches 31.7 dB compared with the direct photon counting measurement.

Select

A novel robust proportional-integral (PI) adaptive observer design for chaos synchronization Mahdi Pourgholi and Vahid Johari Majd Chin. Phys. B, 2011, 20 (12): 120503.   DOI: 10.1088/1674-1056/20/12/120503 Abstract （1612）      PDF （410KB）（1334）       Knowledge map    In this paper, chaos synchronization in the presence of parameter uncertainty, observer gain perturbation and exogenous input disturbance is considered. A nonlinear non-fragile proportional-integral (PI) adaptive observer is designed for the synchronization of chaotic systems; its stability conditions based on the Lyapunov technique are derived. The observer proportional and integral gains, by converting the conditions into linear matrix inequality (LMI), are optimally selected from solutions that satisfy the observer stability conditions such that the effect of disturbance on the synchronization error becomes minimized. To show the effectiveness of the proposed method, simulation results for the synchronization of a Lorenz chaotic system with unknown parameters in the presence of an exogenous input disturbance and abrupt gain perturbation are reported.

Select

Symmetry transformation of nonlinear optical current of tilted Weyl nodes and application to ferromagnetic MnBi2Te4 Zhuo-Cheng Lu(卢倬成) and Ji Feng(冯济) Chin. Phys. B, 2024, 33 (4): 047303.   DOI: 10.1088/1674-1056/ad2bfb Abstract （298）   HTML （1）    PDF （2239KB）（360）       Knowledge map    A Weyl node is characterized by its chirality and tilt. We develop a theory of how nth-order nonlinear optical conductivity behaves under transformations of anisotropic tensor and tilt, which clarifies how chirality-dependent and -independent parts of optical conductivity transform under the reversal of tilt and chirality. Built on this theory, we propose ferromagnetic m MnBi2Te4 as a magnetoelectrically regulated, terahertz optical device, by magnetoelectrically switching the chirality-dependent and -independent DC photocurrents. These results are useful for creating nonlinear optical devices based on the topological Weyl semimetals.

Select

Production of large size single transient cavitation bubbles with tube arrest method Chen Qi-Dai (陈岐岱), Wang Long (王龙) Chinese Physics, 2004, 13 (4): 564-570.   DOI: 10.1088/1009-1963/13/4/028 Abstract （1062）      PDF （3184KB）（579）       Knowledge map    Large size single transient cavitation bubbles of maximum diameter up to 3 cm with sonoluminescence have been generated in water by the ‘tube arrest' method. A simplified one-dimensional model of bubble growing and water column motion is proposed. The results of numerical simulation are compared with the experimental data of the bubble size and oscillation period as the key parameters.

Select

Unveiling the pressure-driven metal-semiconductor-metal transition in the doped TiS2 Jiajun Chen(陈佳骏), Xindeng Lv(吕心邓), Simin Li(李思敏), Yaqian Dan(但雅倩), Yanping Huang(黄艳萍), and Tian Cui(崔田) Chin. Phys. B, 2024, 33 (6): 067104.   DOI: 10.1088/1674-1056/ad4325 Abstract （67）      PDF （1175KB）（68）       Knowledge map    Conventional theories expect that materials under pressure exhibit expanded valence and conduction bands, leading to increased electrical conductivity. Here, we report the electrical properties of the doped 1$T$-TiS$_{2}$ under high pressure by electrical resistance investigations, synchrotron x-ray diffraction, Raman scattering and theoretical calculations. Up to 70GPa, an unusual metal-semiconductor-metal transition occurs. Our first-principles calculations suggest that the observed anti-Wilson transition from metal to semiconductor at 17GPa is due to the electron localization induced by the intercalated Ti atoms. This electron localization is attributed to the strengthened coupling between the doped Ti atoms and S atoms, and the Anderson localization arising from the disordered intercalation. At pressures exceeding 30.5GPa, the doped TiS$_{2}$ undergoes a re-metallization transition initiated by a crystal structure phase transition. We assign the most probable space group as $P$2$_{1}$2$_{1}$2$_{1}$. Our findings suggest that materials probably will eventually undergo the Wilson transition when subjected to sufficient pressure.