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Chinese Physics B 2018年第8期27卷 492-497页

作者： Lin-Peng Yang Qi Li Zi-Xiang Hu Department of Physics Chongqing UniversityChongqing 401331China

By exactly solving the effective two-body interaction for a two-dimensional electron system with layer thickness and an in-plane magnetic field, we recently found that the effective interaction can be described by the generalized pseudopoten- tials （PPs） without the rotational symmetry. With this pseudopotential description, we numerically investigate the behavior of the fractional quantum Hall （FQH） states both in the lowest Landau level （LLL） and first excited Landau level （1LL）. The enhancements of the 7/3 FQH state on the 1LL for a small tilted magnetic field are observed when layer thickness is larger than some critical values, while the gap of the 1/3 state in the LLL monotonically reduced with increasing the in-plane field. From the static structure factor calculation, we find that the systems are strongly anisotropic and finally enter into a stripe phase with a large tilting. With considering the Landau level mixing correction on the two-body interaction, we find the strong LL mixing cancels the enhancements of the FQH states in the 1LL.

关键词： fractional quantum Hall in-plane magnetic field pseudopotentials Landau level mixing

First-Principles Study of Orthorhombic Perovskites MgSiO3 up to 120 GPa and Its Geophysical Implications

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Chinese Physics Letters 2006年第8期23卷 2334-2337页

作者：邓力维赵纪军姬广富龚自正魏冬青 Institute of High Pressure and High Temperature Physics Southwest Jiaotong University Chengdu 610031 College of Advanced Science and Technology Dalian University of Technology Dalian 116023 Laboratory for Shock Wage and Detonation Physics Institute of Fluid Physics Mianyang 621900 Beijing Institute of Spacecraft Environment Engineering Beijing 100094 College of Life Science and Technology Shanghai Jiao Tong University Shanghai 200240 Center for Research in Molecular Modeling (CERMM) Concordia University Montreal Canada

High-pressure behaviour of orthorhombic MgSiO3 perovskite crystal is simulated by using the density functional theory and plane-wave pseudopotentials approach up to 120 GPa pressure at zero temperature. The lattice constants and mass density of the MgSiO3 crystal as functions of pressure are computed, and the corresponding bulk modulus and bulk velocity are evaluated. Our theoretical results agree well with the high-pressure experimental data. A thermodynamic method is introduced to correct the temperature effect on the O-K first-principles results of bulk wave velocity, bulk modulus and mass density in lower mantle PIT range. Taking into account the temperature corrections, the corrected mass density, bulk modulus and bulk wave velocity of MgSiO3-perovskite are estimated from the first-principles results to be 2%, 4%, and 1% lower than the preliminary reference Earth model （PREM） profile, respectively, supporting the possibility of a pure perovskite lower mantle model.

关键词： EARTHS LOWER MANTLE THERMOELASTIC PROPERTIES SILICATE PEROVSKITE THERMALEXPANSIVITY MOLECULAR-DYNAMICS AB-INITIO EQUATION STATE pseudopotentials COMPUTATION

Polymerization of Silicon-Doped Heterofullerenes： an Ab Initio Study

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Chinese Physics Letters 2008年第1期25卷 246-249页

作者：李继玲夏曰源赵明文刘向东宋晨李丽娟李峰黄博达 School of Physics and Microelectronics Shandong University Jinan 250100 Department of Physics Taishan University Tai'an 271021 School of Information Science and Engineering Shandong University Jinan 250100

We perform the calculations on geometric and electronic structures of Si-doped heterofullerene C5oSi10 and its derivatives, a C40Si20-C40Si20 dimer and a C40Si20-based nanowire by using density-functional theory, The optimized configuration of the C40Si20-based nanowire exhibits a regular dumbbell-shaped chain nanostructure. The electronic structure calculations indicate that the HOMO-LUMO gaps of the heterofullerene-based materials can be greatly modified by substitutionally doping with Si atoms and show a decreasing trend with increase cluster size. Unlike the band structures of the conventional wide band gap silicon carbide nanomaterials, the C40Si20- based nanowire has a very narrow direct band gap of 0.087eV.

关键词： CARBON NANOTUBES C-60 FILM pseudopotentials

Ab Initio Comparative Study of Zincblende and Wurtzite ZnO

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Chinese Physics Letters 2007年第4期24卷 1032-1034页

作者：张新宇陈洲文齐彦鹏冯燕赵亮戚力马明臻刘日平王文魁 State Key Laboratory of Metastable Materials Science & Technology Yanshan University Qinhuangdao 066004

By employing the first-principles pseudopotential plane-wave method, the physical properties of zincblende ZnO are investigated in comparison with those of the common wurtzite structure. Zincblende ZnO is predicted to be a direct gap semiconductor. Compared to the wurtzite structure, the zincblende ZnO is characterized by smaller bandgap and pressure coefficient, larger electron effective mass, increasing static dielectric constants and more covalent bonding. Furthermore, the optical properties including dielectric function and energy loss function of zincblende ZnO were obtained and analysed with some features. These aspects reveal promising applications of zincblende ZnO in optoelectronic devices.

关键词： ELECTRONIC-STRUCTURE OPTICAL-PROPERTIES PHOTOEMISSION PRESSURE pseudopotentials SEMICONDUCTORS STATES ALLOY FILMS

First-Principles Prediction of High-Pressure Phase of CaC6

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Chinese Physics Letters 2007年第6期24卷 1668-1670页

作者：李岩张立军崔田刘艳辉马琰铭邹广田 National Lab of Superhard Materials Jilin University Changchun 130012

The lattice dynamics of rhombohedral GaG6 is studied as a function orpressure to probe Its high pressure phase with low superconducting transition temperature using the density functional liner-response theory. The pressureinduced phase transition in CaC6 is attributable to the softening transverse acoustic （TA） phonon mode at the zone boundary X （0.5, 0.0, 0.5） point. The high pressure phase is then explored by performing fully structural optimization in the supercell which accommodates the atomic displacements corresponding to the eigenvectors of the unstable mode of TA（X）. The high-pressure phase is predicted to be a monoclinic unit cell with space group P21/m.

关键词： SUPERCONDUCTIVITY pseudopotentials

Sub-nano Layers of Li, Be, and Al on the Si(100) Surface: Electronic Structure and Silicide Formation

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Semiconductor Science and Information Devices 2023年第1期5卷 11-17页

作者： Victor Zavodinsky Oga Gorkusha Khabarovsk Department of the Institute of Applied Mathematics Far East Branch of the Russian Academy of SciencesKhabarovsk690022Russia

Within the framework of the density functional theory and the pseudopotential method,the electronic structure calculations of the“metal-Si(100)”systems with Li,Be and Al as metal coverings of one to four monolayers(ML)thickness,were carried *** showed that band gaps of 1.02 eV,0.98 eV and 0.5 eV,respectively,appear in the densities of electronic states when the thickness of Li,Be and Al coverings is one *** gaps disappear with increasing thickness of the metal layers:first in the Li-Si system(for two ML),then in the Al-Si system(for three ML)and then in the Be-Si system(for four ML).This behavior of the band gap can be explained by the passivation of the substrate surface states and the peculiarities of the electronic structure of the adsorbed *** common the results can be interpreted as describing the possibility of the formation of a two-dimensional silicide with semiconducting properties in Li-Si(100),Be-Si(100)and Al-Si(100)systems.

关键词： Kohn-Sham method pseudopotentials Si(100)surface Sub-nano metal layers Density of states Two-dimensional silicides Semiconducting properties