期刊文献+
共找到2,491篇文章
< 1 2 125 >
每页显示 20 50 100
Analyzing the surface passivity effect of germanium oxynitride:a comprehensive approach through first principles simulation and interface state density
1
作者 Sheng-Jie Du Xiu-Xia Li +8 位作者 Yang Tian Yuan-Yuan Liu Ke Jia Zhong-Zheng Tang Jian-Ping Cheng Zhi Deng Yu-Lan Li Zheng-Cao Li Sha-Sha Lv 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第5期74-84,共11页
High-purity germanium(HPGe)detectors,which are used for direct dark matter detection,have the advantages of a low threshold and excellent energy resolution.The surface passivation of HPGe has become crucial for achiev... High-purity germanium(HPGe)detectors,which are used for direct dark matter detection,have the advantages of a low threshold and excellent energy resolution.The surface passivation of HPGe has become crucial for achieving an extremely low energy threshold.In this study,first-principles simulations,passivation film preparation,and metal oxide semiconductor(MOS)capacitor characterization were combined to study surface passivation.Theoretical calculations of the energy band structure of the -H,-OH,and -NH_(2) passivation groups on the surface of Ge were performed,and the interface state density and potential with five different passivation groups with N/O atomic ratios were accurately analyzed to obtain a stable surface state.Based on the theoretical calculation results,the surface passivation layers of the Ge_(2)ON_(2) film were prepared via magnetron sputtering in accordance with the optimum atomic ratio structure.The microstructure,C-V,and I-V electrical properties of the layers,and the passivation effect of the Al/Ge_(2)ON_(2)/Ge MOS were characterized to test the interface state density.The mean interface state density obtained by the Terman method was 8.4×10^(11) cm^(-2) eV^(-1).The processing of germanium oxynitrogen passivation films is expected to be used in direct dark matter detection of the HPGe detector surface passivation technology to reduce the detector leakage currents. 展开更多
关键词 Surface passivation High purity germanium detector Germanium nitrogen oxide Interface state density
下载PDF
Local density of optical states calculated by the mode spectrum in stratified media
2
作者 傅廷 陈静瑄 +5 位作者 王学友 戴迎秋 周旭彦 王宇飞 王明金 郑婉华 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第4期135-141,共7页
The local density of optical states(LDOS)is an important physical concept,which can characterize the spontaneous emission of microcavities.In order to calculate the LDOS,the relationship between the mode spectrum and ... The local density of optical states(LDOS)is an important physical concept,which can characterize the spontaneous emission of microcavities.In order to calculate the LDOS,the relationship between the mode spectrum and the LDOS is established.Then,based on the transfer matrix method and the effective resonator model,the leaky loss of the leaky mode and the mode spectrum in the one-dimensional photonic bandgap crystal waveguide are calculated,results of which indicate that the mode spectrum can characterize the leaky loss of the leaky mode.At last,the density of optical states(DOS),and the LDOS in each layer are calculated.The partial DOS and the partial LDOS in the quantum well,related to the fundamental leaky mode,can be used to find out the optimal location of the quantum well in the defect layer to couple more useful photons into the lasing mode for lasers. 展开更多
关键词 local density of optical states mode spectrum transfer matrix method
下载PDF
工业信息物理系统间隙DoS攻击的自适应事件触发稳定控制 被引量:2
3
作者 孙子文 刘加磊 《华南理工大学学报(自然科学版)》 EI CAS CSCD 北大核心 2023年第3期146-156,共11页
针对具有间隙拒绝服务(DoS)攻击的工业信息物理系统(ICPS),研究一种基于观测器的自适应事件触发稳定控制方案。首先构造一个观测器估计系统状态,并采用一种新的自适应事件触发通信方案以节约网络资源;然后通过受频率和持续时间限制的间... 针对具有间隙拒绝服务(DoS)攻击的工业信息物理系统(ICPS),研究一种基于观测器的自适应事件触发稳定控制方案。首先构造一个观测器估计系统状态,并采用一种新的自适应事件触发通信方案以节约网络资源;然后通过受频率和持续时间限制的间隙DoS攻击对ICPS的影响建立攻击模型,将受到DoS攻击的ICPS划分为DoS攻击活跃期系统和DoS攻击休眠期系统,并用一些过去成功触发状态重构当前受到攻击的状态,得到基于动态估计器的攻击补偿机制,保证系统在DoS攻击活跃期间的渐进稳定;最后运用分段Lyapunov泛函方法、Jensen’s不等式和Schur补引理,得到系统的稳定条件,并提出自适应事件触发参数、观测器增益和控制器增益的协同设计方案。用间歇反应器系统模拟间隙DoS攻击下基于自适应事件触发的ICPS系统稳定性能。仿真结果表明,自适应事件触发策略和基于动态估计器的补偿机制不仅能够提升系统的稳定性,还能有效降低数据传输的次数,系统在静态事件触发策略下的触发次数大约是在自适应事件触发策略下的4.5倍。 展开更多
关键词 工业信息物理系统 间隙拒绝服务攻击 自适应事件触发 稳定控制 状态重构 观测器
下载PDF
Discrete vortex bound states with a van Hove singularity in the vicinity of the Fermi level 被引量:1
4
作者 方德龙 崔云康 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第5期644-647,共4页
A theoretical study on discrete vortex bound states is carried out near a vortex core in the presence of a van Hove singularity(VHS) near the Fermi level by solving Bogoliubov–de Gennes(Bd G) equations. When the VHS ... A theoretical study on discrete vortex bound states is carried out near a vortex core in the presence of a van Hove singularity(VHS) near the Fermi level by solving Bogoliubov–de Gennes(Bd G) equations. When the VHS lies exactly at the Fermi level and also at the middle of the band, a zero-energy state and other higher-energy states whose energy ratios follow integer numbers emerge. These discrete vortex bound state peaks undergo a splitting behavior when the VHS or Fermi level moves away from the middle of the band. Such splitting behavior will eventually lead to a new arrangement of quantized vortex core states whose energy ratios follow half-odd-integer numbers. 展开更多
关键词 vortex bound states van Hove singularity Fermi level density of states
下载PDF
Vortex bound states influenced by the Fermi surface anisotropy 被引量:1
5
作者 方德龙 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第3期497-501,共5页
The spatial distribution of vortex bound states is often anisotropic,which is correlated with the underlying property of materials.In this work,we examine the effects of Fermi surface anisotropy on vortex bound states... The spatial distribution of vortex bound states is often anisotropic,which is correlated with the underlying property of materials.In this work,we examine the effects of Fermi surface anisotropy on vortex bound states.The large-scale calculation of vortex bound states is introduced in the presence of fourfold or twofold Fermi surface by solving the Bogoliubov–de Gennes(BdG)equations.Two kinds of quasiparticles’behaviors can be extracted from the local density of states(LDOS)around a vortex.The angle-dependent quasiparticles will move from high energy to low energy when the angle varies from curvature maxima to minima of the Fermi surface,while the angle-independent quasiparticles tend to stay at a relatively higher energy.In addition,the weight of angle-dependent quasiparticles can be enhanced by the increasing anisotropy degree of Fermi surface. 展开更多
关键词 VORTEX ANISOTROPY Fermi surface local density of states
下载PDF
Engineering d-band states of(CuGa)_(x)Zn_(1-2x)Ga_(2)S_(4)material for photocatalytic syngas production
6
作者 Peng Liu Baopeng Yang +7 位作者 Ziyi Xiao Shengyao Wang Shimiao Wu Min Liu Gen Chen Xiaohe Liu Renzhi Ma Ning Zhang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第4期365-372,共8页
The d-band states of catalytic materials participate in adsorbing reactive intermediate species and determine the catalytic behaviors in CO_(2)reduction reactions.However,surface d-band states relating to the photocat... The d-band states of catalytic materials participate in adsorbing reactive intermediate species and determine the catalytic behaviors in CO_(2)reduction reactions.However,surface d-band states relating to the photocatalytic CO_(2)reduction reactions behaviors are rarely concerned.Herein,a slightly amount of Cd^(2+)is decorated on the surface of(CuGa)_(x)Zn_(1-2x)Ga_(2)S_(4)material(Cd^(2+)/(CuGa)_(x)Zn_(1-2x)Ga_(2)S_(4))to tune the surface d-band states for improved CO_(2)+2reduction reactions.The Cd/(CuGa)_(x)Zn_(1-2x)Ga_(2)S_(4)is fabricated via the facile ions-exchange method to make that slightly Zn2+is substituted by Cd^(2+).The Cd^(2+)/(CuGa)_(x)Zn_(1-2x)Ga_(2)S_(4)exhibits much enhanced photocatalytic activity in CO_(2)reduction reactions to produce CO and water splitting to produce H_(2).Physical characterizations show that the energy band structure is not changed obviously.Density functional theory reveals that Cd^(2+)/(CuGa)_(x)Zn_(1-2x)Ga_(2)S_(4)possesses a closer shift of d-band center to Fermi level than(CuGa)_(x)Zn_(1-2x)Ga_(2)S_(4),suggesting easier adsorption of CO_(2)reduction reactive intermediates after Cd^(2+)decoration.Further calculations confirm that a relatively reduced adsorption Gibbs energy of reactive intermediates in CO_(2)reduction reaction is required on Zn atoms in Cd^(2+)/(CuGa)_(x)Zn_(1-2x)Ga_(2)S_(4)material,benefiting the photocatalytic CO_(2)reduction reactions.This work engineers surface d-band states by surface Cd^(2+)decoration,which gives an effective strategy to design highly efficient photocatalysts for syngas production. 展开更多
关键词 Photocatalysisd-band state density functional theory Sulfide semiconductor Surface modification
下载PDF
Valley-dependent topological edge states in plasma photonic crystals
7
作者 李健飞 周晨 +5 位作者 姚静锋 袁承勋 王莹 周忠祥 张景文 Anatoly A KUDRYAVTSEV 《Plasma Science and Technology》 SCIE EI CAS CSCD 2023年第3期6-14,共9页
Plasma photonic crystals designed in this paper are composed of gas discharge tubes to control the flow of electromagnetic waves.The band structures calculated by the finite element method are consistent with the expe... Plasma photonic crystals designed in this paper are composed of gas discharge tubes to control the flow of electromagnetic waves.The band structures calculated by the finite element method are consistent with the experimental results which have two distinct attenuation peaks in the ranges of 1-2.5 GHz and 5-6 GHz.Electromagnetic parameters of the plasma are extracted by the Nicolson-Ross-Weir method and effective medium theory.The measured electron density is between 1×1011 cm-3 and1×1012 cm-3,which verifies the correctness of the parameter used in the simulation,and the collision frequency is near 1.5×1010 Hz.As the band structures are corroborated by the measured scattering parameters,we introduce the concept of photonic topological insulator based on the quantum Valley Hall effect into the plasma photonic crystal.A valley-dependent plasma photonic crystal with hexagonal lattice is constructed,and the phase transition of the valley K(K’)occurs by breaking the spatial inversion symmetry.Valley-spin locked topological edge states are generated and excited by chiral sources.The frequency of the non-bulk state can be dynamically regulated by the electron density.This concept paves the way for novel,tunable topological edge states.More interestingly,the Dirac cone is broken when the electron density increases to 3.1×1012 cm-3,which distinguishes from the methods of applying a magnetic field and changing the symmetry of the point group. 展开更多
关键词 plasma photonic crystal valley-dependent topological state electron density
下载PDF
The Gap Labelling Integrated Density of States for a Quasi Crystal Universe Is Identical to the Observed 4.5 Percent Ordinary Energy Density of the Cosmos 被引量:2
8
作者 Mohamed S. El Naschie 《Natural Science》 2014年第16期1259-1265,共7页
Condense matter methods and mathematical models used in solving problems in solid state physics are transformed to high energy quantum cosmology in order to estimate the magnitude of the missing dark energy of the uni... Condense matter methods and mathematical models used in solving problems in solid state physics are transformed to high energy quantum cosmology in order to estimate the magnitude of the missing dark energy of the universe. Looking at the problem from this novel viewpoint was rewarded by a rather unexpected result, namely that the gap labelling method of integrated density of states for three dimensional icosahedral quasicrystals is identical to the previously measured and theoretically concluded ordinary energy density of the universe, namely a mere 4.5 percent of Einstein’s energy density, i.e. E(O) = mc2/22 where E is the energy, m is the mass and c is the speed of light. Consequently we conclude that the missing dark energy density must be E(D) = 1 - E(O) = mc2(21/22) in agreement with all known cosmological measurements and observations. This result could also be interpreted as a strong evidence for the self similarity of the geometry of spacetime, which is an expression of its basic fractal nature. 展开更多
关键词 E-INFINITY Theory Fractal-Witten M-THEORY GAP Labelling Theorem density of states Dark Energy density Noncommutative Geometry K-THEORY Dimension Group
下载PDF
Research on the Relationship between Density of States and Conducting Properties of Single-walled Carbon Nanotubes 被引量:1
9
作者 ZhenhuaZHANG JingcuiPENG +1 位作者 XiaohuaCHEN JianxiongWANG 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2003年第2期110-112,共3页
The analytical expression of the electronic density of states (DOS) for single-walled carbon nanotubes (SWNTs) has been derived on the basis of graphene approximation of the energy E(k) near the Fermi level EF. The di... The analytical expression of the electronic density of states (DOS) for single-walled carbon nanotubes (SWNTs) has been derived on the basis of graphene approximation of the energy E(k) near the Fermi level EF. The distinctive properties of the DOS, the normalized differential conductivity and the current us bias for SWNTs are deduced and analyzed theoretically. The singularities in the DOS (or in the normalized differential conductivity) predict that the jump structure of current (or conductance)-bias of SWNTs exists. All conclusions from the theoretical analysis are in well agreement with the experimental results of SWNT's electronic structure and electronic transport. In other words, the simple theoretical model in this paper can be applied to understand a range of spectroscopic and other measurement data related to the DOS of SWNTs. 展开更多
关键词 Single-walled carbon nanotubes Graphene approximation of energy Electronic density of states Normalized differential conductivity
下载PDF
Wigner Function:from Ensemble Average of Density Operator to Its Matrix Element in Entangled Pure States 被引量:2
10
作者 FANHong-Yi 《Communications in Theoretical Physics》 SCIE CAS CSCD 2002年第5期533-536,共4页
We show that the Wigner function (an ensemble average of the density operator ρ, Δ is the Wigner operator) can be expressed as a matrix element of ρ in the entangled pure states. In doing so, converting from quant... We show that the Wigner function (an ensemble average of the density operator ρ, Δ is the Wigner operator) can be expressed as a matrix element of ρ in the entangled pure states. In doing so, converting from quantum master equations to time-evolution equation of the Wigner functions seems direct and concise. The entangled states are defined in the enlarged Fock space with a fictitious freedom. 展开更多
关键词 Wigner function ensemble average of density operator matrix element in entangled pure states
下载PDF
Enhancement of refresh time in quasi-nonvolatile memory by the density of states engineering 被引量:1
11
作者 Zhaowu Tang Chunsen Liu +6 位作者 Senfeng Zeng Xiaohe Huang Liwei Liu Jiayi Li Yugang Jiang David Wei Zhang Peng Zhou 《Journal of Semiconductors》 EI CAS CSCD 2021年第2期100-107,共8页
The recently reported quasi-nonvolatile memory based on semi-floating gate architecture has attracted extensive attention thanks to its potential to bridge the large gap between volatile and nonvolatile memory.However... The recently reported quasi-nonvolatile memory based on semi-floating gate architecture has attracted extensive attention thanks to its potential to bridge the large gap between volatile and nonvolatile memory.However,the further extension of the refresh time in quasi-nonvolatile memory is limited by the charge leakage through the p-n junction.Here,based on the density of states engineered van der Waals heterostructures,the leakage of electrons from the floating gate to the channel is greatly suppressed.As a result,the refresh time is effectively extended to more than 100 s,which is the longest among all previously reported quasi-nonvolatile memories.This work provides a new idea to enhance the refresh time of quasi-nonvolatile memory by the density of states engineering and demonstrates great application potential for high-speed and low-power memory technology. 展开更多
关键词 quasi-nonvolatile memory refresh time density of states engineering
下载PDF
Charge Density Wave States and Structural Transition in Layered Chalcogenide TaSe_(2-x)Te_x 被引量:1
12
作者 尉琳琳 孙帅帅 +6 位作者 孙开 刘育 邵定夫 鲁文建 孙玉平 田焕芳 杨槐馨 《Chinese Physics Letters》 SCIE CAS CSCD 2017年第8期108-112,共5页
The structural features and three-dimensional nature of the charge density wave (CDW) state of the layered chalcogenide 1T-TaSe2-xTex (0≤x≤2.0) are characterized by Cs-corrected transmission electron microscopy ... The structural features and three-dimensional nature of the charge density wave (CDW) state of the layered chalcogenide 1T-TaSe2-xTex (0≤x≤2.0) are characterized by Cs-corrected transmission electron microscopy measurements. Notable changes of both average structure and the CDW state arising from Te substitution for Se are clearly demonstrated in samples with x〉0.3. The commensurate CDW state characterized by the known star-of-David clustering in the 1T-TaSe2 crystal becomes visibly unstable with Te substitution and vanishes when x=0.3. The 1T-TaSe2-xTex (0.3≤x≤1.3) samples generally adopt a remarkable incommensurate CDW state with monoclinic distortion, which could be fundamentally in correlation with the strong qq-dependent electron-phonon coupling-induced period-lattice-distortion as identified in TaTe22. Systematic analysis demonstrates that the occurrence of superconductivity is related to the suppression of the commensurate CDW phase and the presence of discommensuration is an evident structural feature observed in the superconducting samples. 展开更多
关键词 Ta TE CDW Charge density Wave states and Structural Transition in Layered Chalcogenide TaSe x)Te_x
下载PDF
Density of excess modes below the first phonon mode in four-dimensional glasses
13
作者 王利近 胥鼎 张世允 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第7期483-489,共7页
Glasses are known to possess low-frequency excess modes beyond the Debye prediction.For decades,it has been assumed that evolution of low-frequency density of excess modes D(ω) with frequency ω follows a power-law s... Glasses are known to possess low-frequency excess modes beyond the Debye prediction.For decades,it has been assumed that evolution of low-frequency density of excess modes D(ω) with frequency ω follows a power-law scaling:D(ω)~ω~γ.However,it remains debated on the value of γ at low frequencies below the first phonon-like mode in finitesize glasses.Early simulation studies reported γ=4 at low frequencies in two-(2D),three-(3D),and four-dimensional(4D)glasses,whereas recent observations in 2D and 3D glasses suggested γ=3.5 in a lower-frequency regime.It is uncertain whether the low-frequency scaling of D(ω)~ω^(3.5) could be generalized to 4D glasses.Here,we conduct numerical simulation studies of excess modes at frequencies below the first phonon-like mode in 4D model glasses.It is found that the system size dependence of D(ω) below the first phonon-like mode varies with spatial dimensions:D(ω) increases in2D glasses but decreases in 3D and 4D glasses as the system size increases.Furthermore,we demonstrate that the ω^(3.5)scaling,rather than the ω~4 scaling,works in the lowest-frequency regime accessed in 4D glasses,regardless of interaction potentials and system sizes examined.Therefore,our findings in 4D glasses,combined with previous results in 2D and 3D glasses,suggest a common low-frequency scaling of D(ω)~ ω^3.5) below the first phonon-like mode across different spatial dimensions,which would inspire further theoretical studies. 展开更多
关键词 vibrational density of states excess modes four-dimensional glasses SCALING computer simulation
下载PDF
Spontaneous-emission control by local density of states of photonic crystal cavity
14
作者 江斌 张冶金 +3 位作者 周文君 陈微 刘安金 郑婉华 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第2期271-276,共6页
The local density of states (LDOS) of two-dimensional square lattice photonic crystal (PhC) defect cavity is studied. The results show that the LDOS in the centre is greatly reduced, while the LDOS at the point of... The local density of states (LDOS) of two-dimensional square lattice photonic crystal (PhC) defect cavity is studied. The results show that the LDOS in the centre is greatly reduced, while the LDOS at the point off the centre (for example, at the point (0.3a, 0.4a), where a is the lattice constant) is extremely enhanced. Further, the disordered radii are introduced to imitate the real devices fabricated in our experiment, and then we study the LDOS of PhC cavity with configurations of different disordered radii. The results show that in the disordered cavity, the LDOS in the centre is still greatly reduced, while the LDOS at the point (0.3a, 0.4a) is still extremely enhanced. It shows that the LDOS analysis is useful. When a laser is designed on the basis of the square lattice PhC rod cavity, in order to enhance the spontaneous emission, the active materials should not be inserted in the centre of the cavity, but located at positions off the centre. So LDOS method gives a guide to design the positions of the active materials (quantum dots) in the lasers. 展开更多
关键词 spontaneous emission local density of states photonic crystal cavity
下载PDF
Valence band structure and density of states effective mass model of biaxial tensile strained silicon based on k·p theory
15
作者 匡潜玮 刘红侠 +2 位作者 王树龙 秦珊珊 王志林 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第12期335-340,共6页
After constructing a stress and strain model, the valence bands of in-plane biaxial tensile strained Si is calculated by k·p method. In the paper we calculate the accurate anisotropy valance bands and the splitti... After constructing a stress and strain model, the valence bands of in-plane biaxial tensile strained Si is calculated by k·p method. In the paper we calculate the accurate anisotropy valance bands and the splitting energy between light and heavy hole bands. The results show that the valance bands are highly distorted, and the anisotropy is more obvious. To obtain the density of states (DOS) effective mass, which is a very important parameter for device modeling, a DOS effective mass model of biaxial tensile strained Si is constructed based on the valance band calculation. This model can be directly used in the device model of metal-oxide semiconductor field effect transistor (MOSFET). It also a provides valuable reference for biaxial tensile strained silicon MOSFET design. 展开更多
关键词 biaxial tensile strained Si k · p theory valance band density of state effective mass
下载PDF
Spin-Split Joint Density of States in GdN
16
作者 Muhammad Azeem 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第2期115-117,共3页
We present an investigation of the optical constants of the near stoichiometric GdN films. Transmission and reflection spectra are collected for the paramagnetic and the ferromagnetic GdN in the photon energy range of... We present an investigation of the optical constants of the near stoichiometric GdN films. Transmission and reflection spectra are collected for the paramagnetic and the ferromagnetic GdN in the photon energy range of 0.5-5.5 eV. In the ferromagnetic phase, behaviors of minority and majority spin states are specifically focussed on, which indicate spin-split joint density of states. The results confirm the LSDA+U estimates of energy gap associated with the majority-spins and also the magnitude of spin splitting. 展开更多
关键词 of on IT in Spin-Split Joint density of states in GdN for
下载PDF
Wigner Function:from Ensemble Average of Density Operator to Its One Matrix Element in Entangled Pure States
17
作者 FAN Hong-Yi 《Communications in Theoretical Physics》 SCIE CAS CSCD 2002年第11期533-536,共4页
We show that the Wigner function W = Tr(△ρ) (an ensemble average of the density operator ρ, △ is theWigner operator) can be expressed as a matrix element of ρ in the entangled pure states. In doing so, converting... We show that the Wigner function W = Tr(△ρ) (an ensemble average of the density operator ρ, △ is theWigner operator) can be expressed as a matrix element of ρ in the entangled pure states. In doing so, converting fromquantum master equations to time-evolution equation of the Wigner functions seems direct and concise. The entangledstates are defined in the enlarged Fock space with a fictitious freedom. 展开更多
关键词 WIGNER function ENSEMBLE AVERAGE of density operator matrix element in ENTANGLED PURE states
下载PDF
Local density of states of dc-biased superlattices with time-dependent imperfection
18
作者 阎维贤 李向荣 《Chinese Physics B》 SCIE EI CAS CSCD 2006年第4期822-827,共6页
The single-particle Green's function for a dc-biased superlattices with single impurity potential varying harmonically with time has been obtained in the framework of U(t,t') method and Floquet-Green's function. ... The single-particle Green's function for a dc-biased superlattices with single impurity potential varying harmonically with time has been obtained in the framework of U(t,t') method and Floquet-Green's function. The calculation of the local density of states shows that new states will emerge between the resonant Wannier-Stark states as a result of the intervention of time-dependent impurity potential, and the increase in electric field strength of impurity will result in the growing of the number of new states between the gaps of neighbouring Stark ladders. 展开更多
关键词 local density of states Floquet-Green's function defects and impurity
下载PDF
Methods for Derivation of Density Matrix of Arbitrary Multi-Mode Gaussian States from Its Phase Space Representation
19
作者 Sheng-Li Zhang Song Yang 《Chinese Physics Letters》 SCIE CAS CSCD 2019年第9期5-9,共5页
We present a method for derivation of the density matrix of an arbitrary multi-mode continuous variable Gaussian entangled state from its phase space representation.An explicit computer algorithm is given to reconstru... We present a method for derivation of the density matrix of an arbitrary multi-mode continuous variable Gaussian entangled state from its phase space representation.An explicit computer algorithm is given to reconstruct the density matrix from Gaussian covariance matrix and quadrature average values.As an example,we apply our method to the derivation of three-mode symmetric continuous variable entangled state.Our method can be used to analyze the entanglement and correlation in continuous variable quantum network with multi-mode quantum entanglement states. 展开更多
关键词 GAUSSIAN MATRIX METHODS for DERIVATION of density MATRIX of ARBITRARY MULTI-MODE GAUSSIAN states from Its Phase Space Representation
下载PDF
Density of States in Two-Dimensional Square Lattices Around Half Filling with Strong Impurities
20
作者 GUYu YANGYong-Hong +1 位作者 WANGYong-Gang ZHANGQun 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第4期743-748,共6页
We calculate the lowest-order quantum-interference correction to the density of states (DOS) of weakly-disordered two-dimensional (2D) tight-binding square lattices around half filling. The impurities are assumed to b... We calculate the lowest-order quantum-interference correction to the density of states (DOS) of weakly-disordered two-dimensional (2D) tight-binding square lattices around half filling. The impurities are assumed to be randomly distributed on small fractions of the sites, and have a-strong potential yielding a unitary-limit scattering. In addition to the usual diffusive modes in the retarded-advanced channel, there appear diffusive pi modes in the retarded-retarded (or advanced-advanced) channel due to the existence of particle-hole symmetry. It is found that the pi-mode diffuson gives rise to a logarithmic suppression to the DOS near the band center, which prevails over the positive correction contributed by pi-mode cooperon. As a result, the DOS is subject to a negative total correction. This result is qualitatively different from the divergent behavior of the DOS at the band center predicted previously for disordered 2D two-sublattice models with the particle-hole symmetry. 展开更多
关键词 WEAK-LOCALIZATION density of states two-dimensional lattice
下载PDF
上一页 1 2 125 下一页 到第
使用帮助 返回顶部