交换关联势对FP-LMTO计算SnTe晶格常数及能带结构的影响

用基于第一性原理的全势能线性Muffin Tin轨道组合 (FP LMTO)方法计算了SnTe的总能 ,给出了体系平衡时的晶格常数及其能带结构 ,并讨论了取不同的交换关联势对计算结果的影响 .

FP-LMTO Calculations of Structural and Electronic Properties of Alkaline-Earth Chalcogenides Alloys AY:A = Ca, Sr, Ba;Y = S

The structural and the electronic properties of the ternary SrxCa1-xS, BaxCa1-xS and BaxSr1-xS alloys have been calculated using the full-potential linear muffin-tin-orbital (FP-LMTO) method based on density functional theory, within both local density approximation (LDA) and generalized gradient approximation (GGA). The calculated equilibrium lattice constants and bulk modulus are compared with previous results. The concentration dependence of the electronic band structure and the direct and indirect band gaps are investigated. Using the approach of Zunger and co-workers, the microscopic origins of the band gap bowing are investigated also. A reason is found from the comparison of our results with other theoretical calculations.

FP-LMTO Investigation of the Structural and Electronic Properties of Cu_xAg_1–xI Alloys

The structural and electronic properties of the ternary CuxAg1–xI, alloy have been calculated, using the full-potential linear muffin-tin-orbital (FP-LMTO) method based on density functional theory, within both the local density approximation and the generalized gradient approximation (GGA). The equilibrium lattice constants and the bulk modulus are compared with previous theoretical calculations. The concentration dependence of the electronic band structure and the direct-indirect band gaps is also investigated. Using the approach of Zunger and co-workers the microscopic origins of the gap bowing were also explained.

全势能线性Muffin-Tin轨道组合分子动力学方法及其在半导体团簇结构计算中的应用

研究原子团簇的结构及其与之相关的物理和化学的性质是当前国际上一个活跃的研究前沿。全势能线性Muffin Tin轨道组合法是目前国际上最先进的第一性原理分子动力学方法之一。本文简要地阐述了全势能线性Muffin Tin轨道组合法的原理 ,以及本研究小组用此方法在半导体原子团簇结构研究中的部分结果。

Ground state parameters,electronic properties and elastic constants of CaMg3:DFT study

The present study aims to investigate the equation of state(EOS)parameters of CaMg3 in aReCh(D09),AIFR(DO3),CU3A11(LI2)and CuTi3(L60)structures,using full potential linear muffin-tin orbitals(FP-LMTO)approach based on the density functional theory(DFT).The local density approximation(LDA)and the generalized gradient approximation(GGA)were both applied for the exchange-correlation potential term.The calculated equation of slate parameters at equilibrium,in general,agreed well with the available data of the literature.The calculations showed that under compression CaMg3 transforms from DO3 to DO9 at about 29.96GPa,and 25.1 GPa using LDA and GGA,respectively.The elastic constants C,y,aggregate moduli,Vickers hardness,sound velocity,and Debye temperature of CaMg3 in D03 structure were also reported,discussed and analyzed.Using LDA(GGA),the calculated values of Hv andθD were found at around 5.80GPa(5.93GPa)and 393.44 K(389.91 K),respectively.Electronic band structure,total density of states(TDOS)as well as the partial density of states(PDOS)have been also obtained.The electronic band structure confirms the metallic behavior of CaMg3 in DO3 phase,the valence bands are dominated by the maximum contribution of‘d’like states of Ca in the energy ranging from 2 to 3 eV for GGA,and from 4.5 to 5 eV for LDA,respectively.

Theoretical Study on the Origins of the Gap Bowing in Mg_xZn_1–xO Alloys

The full potential linear muffin-tin orbital (FP-LMTO) method was applied to study the structural and electronic properties of the compounds MgO, ZnO and their alloy MgxZn1–xO in the zincblende and NaCl structures. Results are obtained using the local density approximation (LDA), the ground-state properties like lattice constant and bulk modulus obtained agree very well with experimental and other theoretical calculations. The effect of composition on lattice constant from Vegard’s law and the bulk modulus was investigated. The microscopic origins of the gap bowing were explained by using the approach of Zunger and co-workers. It is concluded that the energy band gap bowing is primarily due to chemical charge-transfer effect. Contribution of volume deformation and structural relaxation to the gap bowing parameter is found to be very small.

<i>Ab Initio</i>Calculations Study of Structural and Electronic Properties of Ternary Alloy Al_xIn_1–xAs

First principles calculations of the structural and electronic properties of AlAs, InAs and their alloy AlxIn1–xAs have been performed using the full-potential linear muffin-tin orbital (FP-LMTO) [1] method within density functional theory (DFT) [2,3]. We used the local density approximation (LDA) [4] within the generalized gradient correction (GGA) [5] to calculate the electronic structure at equilibrium volume. The effect of composition on lattice constants, bulk modulus and band gap were investigated. Deviations of the lattice constants from Vegard’s law and the bulk modulus were observed for this alloy. The microscopic origins of the gap bowing were explained by using the approach of Zunger and co-workers [6-9].

First Principles Study of Structural and Electronic Properties of O_xS₁_-_xZn Ternary Alloy

We perform self-consistent ab-initio calculations to study the structural and electronic properties of zinc blende ZnS, ZnO and their alloy. The full-potential muffin-tin orbitals (FP-LMTO) method was employed within density functional theory (DFT) based on local density Approximation (LDA), and generalized gradient approximation (GGA). We analyze composition effect on lattice constants, bulk modulus, band gap and effective mass of the electron. Using the approach of Zunger and coworkers, the microscopic origins of band gap bowing have been detailed and explained. Discussions will be given in comparison with results obtained with other available theoretical and experimental results.

Physical Properties of the Zn_xCd_1-xSe Alloys: Ab-Initio Method

The present work performs self-consistent ab initio full-potential linear muffin-tin orbital (FP-LMTO) method to study the structural and electronic properties of the ternary ZnxCd1-xSe alloy, based on density functional theory (DFT). In this approach, both the local density approximation (LDA) and the generalized gradient approximation (GGA) were used for the exchange-correlation potential calculation. The ground-state properties are determined for the bulk materials CdSe, ZnSe and their alloy in cubic phase. In particular, the lattice constant, bulk modulus, electronic band structures and effective mass. We mainly showed deviation of the lattice parameter and bulk modulus from Vegard’s law of our alloys. We also presented the microscopic origins of the gap bowing using the approach of Zunger et al. The results are compared with other theoretical calculations and experimental data and are in reasonable agreement.

Structural and Electronic Properties Calculations of Al _xIn_1-xP Alloy

The equilibrium structure and the electronic properties of III-V zinc-blende AlP, InP semiconductors and their alloy have been studied in detail from first-principles calculations. A full-potential linear muffin-tin-orbital (FP-LMTO) method has been used in conjunction with both the local-density approximation (LDA) and the generalized-gradient approximation (GGA) to investigate the effect of increasing the concentration of aluminum on the structural properties such as the lattice constants and the bulk moduli. Besides, we report the concentration dependence of the electronic band structure, the direct-indirect band gap crossovers and bowing. Using the approach of Zunger and co-workers the microscopic origins of the gap bowing were also explained. A reasonable agreement is found in comparing our results with other theoretical calculations.

<i>Ab Initio</i>Study of Structural and Electronic Properties of Barium Chalcogenide Alloys

First-principles calculations have been used to study the structural and electronic properties of BaS1–xSex ternary alloy using full-potential muffin-tin orbital’s (FP-LMTO) method within density functional theory (DFT). In this approach, the local-density approximation (LDA) and generalized gradient approximation (GGA) are used for the exchange-correlation (XC) potential. The effect of composition on lattice parameter, bulk modulus, band gap and effective mass was investigated. The deviations of the lattice constant from Vegard’s law and the bulk modulus from linear concentration depend- ence were observed for BaS1–xSex alloy. The microscopic origins of bowing parameter were explained using approach of Zunger and co-workers. Accordance is found from the comparison of our results with other experimental and theo- retical calculations.

重电子化合物LiV_2O_4的电子结构

用第一性原理的FP-LMTO能带计算方法研究了重电子化合物LiV2O4的电子结构.结果表明,Fermi面附近的导带是由V原子的3d电子形成的宽度为2.5eV的窄能带,是3d态在立方晶体场中具有t2g对称性的子带;它与O的2p轨道构成的能带约有1.9eV的能隙.计算得出的Fermi能处电子态密度和线性电子比热系数分别是11.1（staes/eV·f-1·u-1.）和26.7mJ/mol·K2.Fermi面处的能带色散具有电子型和空穴型两种,呈现出一种复杂的Fermi面结构.LSDA以及GGA计算表明,LiV2O4有一个磁矩为1.13μB/钒原子,总能比LDA基态低约148meV/f·u.的铁磁性基态.由目前的能带结构计算的结果无法确定这一类Kondo体系的局域磁矩的来源,表明这一化合物中的重电子行为可能有别于在含有4f和5f稀土的重电子合金中观察到的局域磁矩与传导电子的交换作用机制,其中存在量子相变的可能.

铁在高压下的结构与磁性的全势的线性Muffin-tin轨道研究

采用全势的线性Muffin tin轨道 (FP LMTO)方法对铁在高压下的结构和磁性进行了系统的研究 .对铁存在的三种结构bcc,fcc和hcp分别以三种磁性耦合机理在很宽的体积范围内进行了计算 ,得到系统的总能、磁矩随体积变化的关系 ;导出了压强与体积、体弹性模量与体积的关系曲线 ;讨论了各相在不同范围内的稳定性 ;估算了α→ε相之间的转变压强 ;并把得到的结果与实验进行了比较 。