期刊文献+
共找到113篇文章
< 1 2 6 >
每页显示 20 50 100
First-principles Study on the Electronic Structure and Stability of Mo_(2-x)Cr_xC
1
作者 汪向荣 闫牧夫 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2009年第S1期37-40,共4页
This paper deals with the electronic structure and stability of a series of carbides Mo2-xCrxC based on the pseudopotential plane-waves approach of density functional theory and using the generalized gradient approxim... This paper deals with the electronic structure and stability of a series of carbides Mo2-xCrxC based on the pseudopotential plane-waves approach of density functional theory and using the generalized gradient approximation(GGA) for the exchange and correlation potential.The calculation results of formation energies demonstrate that the structure Mo2-xCrxC in range of 0≤x≤1.75 is stable under ambient conditions.The formation energies/stabilities of the structures Mo2-xCrxC increase /reduce with enhancing the content of Cr in the structure.Calculated density of state(DOS) show that an increase in the content of Cr dissolving in Mo2-xCrxC crystal cell can lead to the crystal cell volume slightly to shrinkage,TDOS to be elevated at the Fermi level and the peak value of DOS to decrease at the lower energy region from-13.78 to-10.16 eV.Mulliken population analysis explains that the Mo2-xCrxC phase possess the metallic,covalent and ionic bonds. 展开更多
关键词 Mo2-xCrxC structure first-principles calculations electronic structure stability density of state
下载PDF
Structural, elastic and electronic properties of Cu-X compounds from first-principles calculations 被引量:1
2
作者 刘洋 汪炯 +1 位作者 高倩男 杜勇 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第5期1585-1594,共10页
The structural, elastic and electronic properties of Cu-X compounds in the Cu-X(X =Al, Be, Mg, Sn, Zn and Zr) systems were predicted systematically by first-principles calculations. The ground state properties such as... The structural, elastic and electronic properties of Cu-X compounds in the Cu-X(X =Al, Be, Mg, Sn, Zn and Zr) systems were predicted systematically by first-principles calculations. The ground state properties such as lattice constant, bulk modulus(B)and it's pressure derivative(B') were predicted by fitting a four-parameter Birch–Murnaghan equation and the elastic constants(cij′s)are determined by an efficient strain-stress method. The calculated lattice parameters and cij′s of these binary compounds agree well with the available experimental data in the literature. In addition, elastic properties of polycrystalline aggregates including bulk modulus(B), shear modulus(G), elastic modulus(E), B/G(bulk/shear) ratio, and anisotropy ratio(AU) are calculated and compared with the experimental and theoretical results available in the literature. Based on electronic density of states(DOS) analysis, it can be revealed that all the compounds in the present work are metallic in nature. 展开更多
关键词 Cu-X compounds structural properties elastic properties electronic properties first-principles
下载PDF
First-Principles Investigation of Energetics and Electronic Structures of Ni and Sc Co-Doped MgH2 被引量:3
3
作者 Gaili Sun Yuanyuan Li +2 位作者 Xinxin Zhao Yiming Mi Lili Wang 《American Journal of Analytical Chemistry》 2016年第1期34-42,共9页
First-principles calculations were used to study the energetics and electronic structures of Ni and Sc co-doped MgH<sub>2</sub> system. The preferential positions for dopants were determined by the minimal... First-principles calculations were used to study the energetics and electronic structures of Ni and Sc co-doped MgH<sub>2</sub> system. The preferential positions for dopants were determined by the minimal total electronic energy. The results of formation enthalpy indicate that Ni and Sc co-doped MgH<sub>2</sub> system is more stable than Ni single-doped system. The hydrogen desorption enthalpies of these two hydrides are investigated. Ni and Sc co-doping can improve the dehydrogenation properties of MgH<sub>2</sub>. The lowest hydrogen desorption enthalpy of 0.30 eV appears in co-doped system, which is significantly lower than that of Ni doping. The electronic structure analysis illustrates that the hybridization of dopants with Mg and H atom together weakens the Mg-H interaction. And the Mg-H bonds are more susceptible to dissociate by Ni and Sc co-doping because of the reduced magnitude of Mg-H hybridization peaks. These behaviors effectively improve the dehydrogenation properties of Ni and Sc co-doped cases. 展开更多
关键词 first-principles Calculation MgH2 stability ENTHALPY Dehydrogenation Property electronic structure
下载PDF
First-principles investigation of the phase stability of MgAl_2 compounds
4
作者 陈蓉 陈敬超 潘勇 《Journal of Beijing Institute of Technology》 EI CAS 2012年第1期122-127,共6页
First-principles have been calculated to investigate the phase stabilities of the intermetallic phase of MgAl2 compounds by electronic structures and the charge distribution maps. The first-prin- ciples employed the n... First-principles have been calculated to investigate the phase stabilities of the intermetallic phase of MgAl2 compounds by electronic structures and the charge distribution maps. The first-prin- ciples employed the norm-conserving pseudo potential density functional method. They were calcu- lated both with the Ceperley and Alder data as parameterized by Perdew and Zunger(CA-PZ) of local-density approximation (LDA) and with the Perdew Burke Eruzerh (PBE) form of gradient-corrected approximation (GGA). A better method was found by comparing results from these two ultrasoft pseudo potentials. The present calculations indicate that LDA is better than GGA compared with references. This work also compared the lattice parameters, cohesive energy, formation enthalpy and electronic structure between theoretical results and experimental measurements (where available ). The calculations indicate that the unit cell volume get smaller after optimized and cohesive energy and formation enthalpy of C14 structure is the highest. The calculated structures are stable and the stability is aligned as C36 〈 C15 〈 C14. 展开更多
关键词 MgAl2 compounds electronic structure phase stability first-principles
下载PDF
A Density Functional Theory Study of the Geometric and Electronic Structure of MgF_2 (110) Surface
5
作者 王丽平 HAN Peide +2 位作者 ZHANG Caili HAO Yuying 许并社 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2013年第1期22-25,共4页
Abstract" Ab initio density functional theory (DFT) was employed to study geometric and electronic structure of MgF2 (110) surface. Three different clean surface models have been considered. The results show that... Abstract" Ab initio density functional theory (DFT) was employed to study geometric and electronic structure of MgF2 (110) surface. Three different clean surface models have been considered. The results show that the surface terminated with one-layer F has the smallest relaxation and the lowest surface energy, which indicates this model is the most energetically favorable structure of MgF2(110) surface. Furthermore, the electronic properties are also discussed from the point of density of states and charge density. Analysis of electronic structure shows that the band gap of the surface is significantly narrowed with respect to the bulk. The electrons of the surface exhibit strong locality and larger effective mass. 展开更多
关键词 geometric structure electronic structure stability surface energy first principles
下载PDF
Structural, elastic, and electronic properties of sodium atoms encapsulated type-I silicon–clathrate compound under high pressure
6
作者 张伟 陈青云 +1 位作者 曾召益 蔡灵仓 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第10期400-407,共8页
We calculated the structural, elastic, and electronic properties of alkali metal Na atoms doped type-I silicon-clathrate compound(Na8Si46) under pressure using first-principles methods. The obtained dependencies of ... We calculated the structural, elastic, and electronic properties of alkali metal Na atoms doped type-I silicon-clathrate compound(Na8Si46) under pressure using first-principles methods. The obtained dependencies of bond lengths and bond angles on pressure show heterogeneous behaviors which may bring out a structural transition. By using the elastic stability criteria from the calculated elastic constants, we confirm that the Na8Si46 is elastically unstable under high pressure. Some of the mechanical and thermal quantities include bulk modulus, shear modulus,Young's modulus, Debye temperature,sound velocity, melting point, and hardness, which are also derived from the elastic constants. The calculated total and partial electron densities of states of Na8Si46 indicate a weak interaction between the encapsulated Na atoms and the silicon framework. Moreover, the effect of pressure on its electronic structure is also investigated, which suggests that pressure is not a good choice to enhance the thermoelectricity performance of Na8Si46. 展开更多
关键词 clathrate compound elastic constants electronic structure density functional theory
下载PDF
Structural stability and electronic properties of carbon star lattice monolayer
7
作者 范雪兰 牛春要 +2 位作者 王新全 王建涛 李捍东 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第9期310-313,共4页
By means of the first-principles calculations, we have investigated the structural stability and electronic properties of carbon star lattice monolayer and nanoribbons. The phase stability of the carbon star lattice i... By means of the first-principles calculations, we have investigated the structural stability and electronic properties of carbon star lattice monolayer and nanoribbons. The phase stability of the carbon star lattice is verified through phononmode analysis and room temperature molecular dynamics simulations. The carbon star lattice is found to be metallic due to the large states across the Fermi-level contributed by Pz orbital. Furthermore, the nanoribbons are also found to be metallic and no spin polarization occurs, except for the narrowest nanoribbon with one C12 ring, which has a ferromagnetic ground state. Our results show that carbon star lattice monolayer and nanoribbons have rich electronic properties with great potential in future electronic nanodevices. 展开更多
关键词 carbon star lattice structural stability electronic properties first-principles calculations
下载PDF
First-Principles Investigation of the Effect of M-Doped (M = Zr, Hf) TiCoSb Half-Heusler Thermoelectric Material
8
作者 Gaili Sun Yuanyuan Li +2 位作者 Xinxin Zhao Yiming Mi Lili Wang 《Journal of Materials Science and Chemical Engineering》 2015年第12期78-86,共9页
The M-doping (M = Zr, Hf) effects on the electronic structures and thermoelectric performance of TiCoSb were studied by first-principles calculations. The band structure analysis shows that substituting Ti with M does... The M-doping (M = Zr, Hf) effects on the electronic structures and thermoelectric performance of TiCoSb were studied by first-principles calculations. The band structure analysis shows that substituting Ti with M does not change the band structures of these systems significantly. Most of the M-doped systems have a lower band gap value than that of TiCoSb;especially Ti0.5Zr0.5CoSb has the lowest energy band gap value of 0.971 eV. Besides, the amplitudes of the density of states in the region of the valence bands for M-doped systems show a similar but slightly higher value than TiCoSb. Those suggest that these compounds could have better thermoelectric performance than TiCoSb. The phonon dispersion relations show that the larger mass of Zr/Hf with respect to Ti lowers the optical modes and induces mixing with the acoustic branches. Our calculations offer a valuable insight on how to characterize complicated crystal structures of thermoelectric materials and optimize the material composition. 展开更多
关键词 Half-Heusler COMPOUND THERMOELECTRIC first-principles electronic structure
下载PDF
B位掺杂提升CsSnI_(3)钙钛矿结构和电荷稳定性的第一性原理研究
9
作者 赵思健 葛治中 杨旭东 《原子与分子物理学报》 CAS 北大核心 2025年第6期144-152,共9页
全无机CsSnI_(3)钙钛矿拥有理想的带隙宽度(1.3 eV),光电转化效率理论峰值达到33%.目前CsSnI_(3)太阳能电池的发展受制于的CsSnI_(3)的结构不稳定性和Sn^(2+)易被氧化为Sn^(4+)的问题.研究基于第一性原理,详细探讨了一系列金属元素对CsS... 全无机CsSnI_(3)钙钛矿拥有理想的带隙宽度(1.3 eV),光电转化效率理论峰值达到33%.目前CsSnI_(3)太阳能电池的发展受制于的CsSnI_(3)的结构不稳定性和Sn^(2+)易被氧化为Sn^(4+)的问题.研究基于第一性原理,详细探讨了一系列金属元素对CsSnI_(3)进行B位掺杂改性的方案,旨在提升CsSnI_(3)结构稳定性,并抑制CsSnI_(3)中Sn^(2+)被氧化为Sn^(4+)的问题.计算结果表明,在CsSnI_(3)钙钛矿B位掺杂三价金属Sb、Bi能够阻碍CsSnI_(3)相变生成Cs_(2)SnI_6,并且抑制Sn^(2+)的氧化;尤其在晶格中存在锡空位缺陷时,Sb、Bi掺杂对于Sn^(4+)形成的抑制效果更为显著.同时,低浓度的Sb、Bi掺杂不会改变CsSnI_(3)的直接带隙特性,且带隙宽度变化较小,因此能够在维持CsSnI_(3)优良光电活性的基础上进一步提高结构和电荷的稳定性.研究结果为实现高效且稳定的CsSnI_(3)钙钛矿太阳能电池提供了重要的理论指导. 展开更多
关键词 全无机锡基钙钛矿 第一性原理 B位掺杂 相稳定性 电子结构
下载PDF
Influence of Nb and Mo contents on phase stability and elastic property of β-type Ti-X alloys 被引量:2
10
作者 姚强 孙坚 +1 位作者 邢辉 郭文渊 《中国有色金属学会会刊:英文版》 EI CSCD 2007年第6期1417-1421,共5页
The energetic, electronic structure and elastic property of β-type Ti1-xXx (X=Nb and Mo, x=0.041 7, 0.062 5, 0.125 0, 0.187 5, 0.250 0, 0.312 5 and 0.375) binary alloys were calculated by the method of supercell and ... The energetic, electronic structure and elastic property of β-type Ti1-xXx (X=Nb and Mo, x=0.041 7, 0.062 5, 0.125 0, 0.187 5, 0.250 0, 0.312 5 and 0.375) binary alloys were calculated by the method of supercell and augmented plane waves plus local orbitals within generalized gradient approximation. The elastic moduli of the polycrystals for these Ti1-xXx alloys were calculated from the elastic constants of the single crystal by the Voigt-Reuss-Hill averaging method. Based on the calculated results, the influence of X content on the phase stability and elastic property of β-type Ti1-xXx alloys was investigated. The results show that the phase stability, tetragonal shear constant C′, bulk modulus, elastic modulus and shear modulus of β-type Ti1-xXx alloys increase with an increase of X content monotonously. When the valence electron number of β-type Ti1-xXx alloys is around 4.10, i.e. the content of Nb is 9.87% (molar fraction) in the Ti-Nb alloy and Mo is 4.77% (molar fraction) in Ti-Mo alloy, the tetragonal shear constant is nearly zero. The Ti1-xXx alloys achieve low phase stability and low elastic modulus when the tetragonal shear constant reaches nearly zero. In addition, the phase stability of β-type Ti1-xXx alloys was discussed together with the calculated electronic structure. 展开更多
关键词 钛合金 弹性特性 相位稳定性 电子结构
下载PDF
Theoretical Studies on the Thermo- electric Properties of Tin-based Clathrates:Cs_8M_4Sn_(42)(M=Zn,Cd,Hg) and Cs_8Sn_(44)□_2
11
作者 WANG Peng WU Li-Ming 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2013年第12期1793-1804,共12页
The site occupancies and thermoelectric properties of tin-based clathrates Cs8M4Sn44□2 (M = Zn, Cd, Hg) and CssSn44□2 were studied by the first principle calculations. We had provided an efficient way to probe the... The site occupancies and thermoelectric properties of tin-based clathrates Cs8M4Sn44□2 (M = Zn, Cd, Hg) and CssSn44□2 were studied by the first principle calculations. We had provided an efficient way to probe the relationship between the crystalline structure and power factor. Detailed analyses indicated the p states of Sn at 16i and 24k sites together with the p states of M substitute contributed significantly to the maximum power factor, yet Cs atoms nearly did not. The dangling bonds of vacancies in Cs8Snn44□2 are also discussed. The power factors of p- and n-type CssMaSn42 and Cs8Sn44□2 at optimal temperature and carder concentration are predicted. Our results suggest that Cs8ZnaSn44□2 is a promising candidate at the 5.25 ×10^19 cm-3 hole carrier concentration as a high temperature thermoelectric material that is competitive to the state-of-art Ge-based clathrate thermoelectric materials. 展开更多
关键词 the first principle THERMOELECTRIC boltzmann theory clathrate tin electronic structure
下载PDF
W掺杂Ti(C_(0.5)N_(0.5))的电子结构及力学性能的理论分析
12
作者 熊萧 董定乾 +4 位作者 熊健松 贺逢源 陈鑫辉 熊慧文 张立 《硬质合金》 CAS 2024年第1期1-11,共11页
采用密度泛函理论(DFT)的第一性原理方法对金属原子W掺杂Ti(C_(0.5)N_(0.5))的晶格常数、弹性常数和电子结构以及电荷布居进行计算和分析,结果表明:W原子可稳定存在于(Ti_(1-x)W_(x))(C_(0.5)N_(0.5))中,但W原子的加入使得(Ti_(1-x)W_(x... 采用密度泛函理论(DFT)的第一性原理方法对金属原子W掺杂Ti(C_(0.5)N_(0.5))的晶格常数、弹性常数和电子结构以及电荷布居进行计算和分析,结果表明:W原子可稳定存在于(Ti_(1-x)W_(x))(C_(0.5)N_(0.5))中,但W原子的加入使得(Ti_(1-x)W_(x))(C_(0.5)N_(0.5))体系稳定性下降,增强了原子间的键能,且晶格因替换原子W与Ti的直径大小不同产生畸变,并伴随着W含量的增加会加剧晶格畸变和晶格常数失衡;由弹性常数计算结果表明,适当添加W原子能改善(Ti_(1-x)W_(x))(C_(0.5)N_(0.5))的抵抗外力变形的能力和硬度,同时可以降低晶体的脆性,且当x(W)=12%时,(Ti_(1-x)W_(x))(C_(0.5)N_(0.5))抵抗变形能力和硬度达到最佳,理论硬度HV提高了6%;电子结构计算结果显示,W原子掺杂后费米能级处态密度增加,增强了(Ti_(1-x)W_(x))(C_(0.5)N_(0.5))的导电性,且远高于Ti(C_(0.5)N_(0.5))的导电性;通过差分电荷密度图发现,W原子掺杂替换Ti会与C原子形成极性共价键,可以改善(Ti_(1-x)W_(x))(C_(0.5)N_(0.5))的固有力学性能。 展开更多
关键词 TICN 第一性原理 稳定性 力学性能 电子结构
下载PDF
金属间化合物CuBe和CuBe_(2)的力学和电子结构性质研究
13
作者 陈雨轩 殷蕊 +1 位作者 陈磊 张美光 《宝鸡文理学院学报(自然科学版)》 CAS 2024年第2期20-27,共8页
目的 探究金属间化合物CuBe和CuBe_(2)的弹性力学行为和电子结构特征,以期对Cu-Be二元合金的力学强化机制有直观和深刻的理解。方法 采用基于密度泛函理论的第一性原理和基于“应变-应力”的计算方法。结果 CuBe和CuBe_(2)晶格参数的理... 目的 探究金属间化合物CuBe和CuBe_(2)的弹性力学行为和电子结构特征,以期对Cu-Be二元合金的力学强化机制有直观和深刻的理解。方法 采用基于密度泛函理论的第一性原理和基于“应变-应力”的计算方法。结果 CuBe和CuBe_(2)晶格参数的理论计算值与实验结果一致,单晶弹性常数结果表明这2种材料均满足弹性力学稳定判据;由Be-Be强共价键构成的Be三棱锥是CuBe_(2)具有优异力学性能的主要原因;CuBe和CuBe_(2)这2种金属间化合物中同时存在金属键、离子键和共价键的复杂成键特征。结论 Be原子含量的增加可以有效提升Cu-Be合金中金属间化合物的拉伸和剪切强度,但是会减弱合金的韧性和延展性。 展开更多
关键词 金属间化合物 第一性原理计算 力学性质 电子结构
下载PDF
First-Principle Investigation of the Structural Stability and Electronic Property of Precipitates on the Cu-Rich Side of Cu-Ni-Si Alloys 被引量:1
14
作者 龙永强 刘平 +2 位作者 刘勇 贾淑果 田宝红 《Journal of Shanghai Jiaotong university(Science)》 EI 2011年第3期266-271,共6页
The energetic and electronic structures of precipitates on the Cu-rich side of Cu-Ni-Si alloys were investigated by using the first-principle calculations based on plane-wave pseudopotential method.The negative format... The energetic and electronic structures of precipitates on the Cu-rich side of Cu-Ni-Si alloys were investigated by using the first-principle calculations based on plane-wave pseudopotential method.The negative formation heats and the cohesive energies of these precipitates were estimated with electronic structure calculations, and their structural stability was also analyzed.The results show thatδ-Ni2Si,γ-Ni5Si2 andβ-Ni3Si precipitates all have great alloying ability and structural stability,which,after comparing their density of states (DOS),is found attributed to the pseudogap effect near the Fermi level(Ef)and strong hybridization between the Ni-3d and Si-3p states.Compared with the other two precipitates,theδ-Ni2Si precipitate has the greatest structural stability,which is resulted from its lower DOS at Ef and the main bonding peaks slightly moving to the low energy region. 展开更多
关键词 PRECIPITATE first-principles electronic structure structural stability Cu-Ni-Si alloy
原文传递
具有五元环结构的二维硼化物的第一性原理研究
15
作者 杨俊峰 杨艳萍 +3 位作者 刘宇 刘荣 王帅宇 李锋钰 《内蒙古工业大学学报(自然科学版)》 2024年第6期503-511,共9页
通过密度泛函理论(DFT)计算预测了三种具有五元环特征构型的二维硼化物结构,即penta-B_(4)X_(2)(X=S,Se,Te)。计算结果表明,三种penta-B_(4)X_(2)结构均表现出了良好的热力学、动力学、热学和力学稳定性。从结构上来看,penta-B_(4)X_(2... 通过密度泛函理论(DFT)计算预测了三种具有五元环特征构型的二维硼化物结构,即penta-B_(4)X_(2)(X=S,Se,Te)。计算结果表明,三种penta-B_(4)X_(2)结构均表现出了良好的热力学、动力学、热学和力学稳定性。从结构上来看,penta-B_(4)X_(2)结构中的B—X共价键以及B—B共价键的共存有助于五边形框架的结构稳定性。此外,三种单层结构都具有较高的面内杨氏模量(最低为90.67 Nm^(-1)),其中二维penta-B_(4)Se_(2)单层在特定面内角方向上具有负泊松比(NPR)。电子能带结构表明所有单层结构都具有适中带隙(1.04、1.17、1.28 e V)的半导体材料。三种二维pentaB_(4)X_(2)对于不同波段的光波均具有较强的吸收系数,可见光区最高可达3.5×10~5 cm^(-1)的数量级,紫外光区域则表现出更强的光吸收能力。优异的光吸收性能使得二维penta-B_(4)X_(2)结构成为潜在的光致水解材料。 展开更多
关键词 二维硼化物 第一性原理计算 结构与稳定性 力学性质 电子结构 光学性质
下载PDF
Mg-Ce化合物相结构稳定性的赝势平面波方法研究 被引量:9
16
作者 周惦武 彭平 +1 位作者 胡艳军 刘金水 《稀有金属材料与工程》 SCIE EI CAS CSCD 北大核心 2006年第6期871-875,共5页
采用基于密度泛函理论的第一原理赝势平面波方法,计算了Mg-Ce二元合金系中不同Ce原子浓度与结构类型金属间化合物的几何、能态与电子结构,并从合金形成热和结合能两方面调查了这些金属间化合物不同结构类型的相结构稳定性。结果表明:Mg3... 采用基于密度泛函理论的第一原理赝势平面波方法,计算了Mg-Ce二元合金系中不同Ce原子浓度与结构类型金属间化合物的几何、能态与电子结构,并从合金形成热和结合能两方面调查了这些金属间化合物不同结构类型的相结构稳定性。结果表明:Mg3Ce,Mg2Ce,MgCe,MgCe2和MgCe3金属间化合物具有最强合金化形成能力和最高结构稳定性的结构类型分别为DO3,C15,Ba,C15和DO3。电子态密度(DOS)的分析结果表明:不同Ce含量Mg-Ce金属间化合物相结构稳定性的差异源于其费米能级处电子数的不同,高稳定性的相结构类型可归因于其费米能级处较少的Mg(3s),Mg(2p),Ce(5d)和Ce(4f)成键电子。 展开更多
关键词 Mg-Ce金属间化合物 第一原理计算 结构稳定性 电子结构
下载PDF
基于第一性原理的Ⅷ型Ba_(8)Ga_(16-x)Al_(x)Sn_(30)(x=0,6,16)笼合物结构稳定性及电子结构性质 被引量:4
17
作者 申兰先 李德聪 +4 位作者 申开远 郑杰 刘祖明 葛文 邓书康 《功能材料》 EI CAS CSCD 北大核心 2021年第3期3194-3199,共6页
基于密度泛函的第一性原理从理论上探索Ba_(8)Ga_(16-x)Al_(x)Sn_(30)(x=0,6,16)笼合物的电子能带结构和结构稳定性。结果表明,Al置换Ga后笼合物的晶格常数增加,当Al部分置换Ga时笼合物结构稳定性增强;Ba_(8)Ga_(10)Al_(6)Sn_(30)笼合... 基于密度泛函的第一性原理从理论上探索Ba_(8)Ga_(16-x)Al_(x)Sn_(30)(x=0,6,16)笼合物的电子能带结构和结构稳定性。结果表明,Al置换Ga后笼合物的晶格常数增加,当Al部分置换Ga时笼合物结构稳定性增强;Ba_(8)Ga_(10)Al_(6)Sn_(30)笼合物由于费米能级附近能带较密集会表现出较好的电传输特性;在费米能级附近,Ba_(8)Al_(16)Sn_(30)具有较高的态密度,且态密度线更陡峭,这有利于提高材料的Seebeck系数,然而也可能引起材料结构的稳定性下降。这些结果为进一步研究Ba8Ga16Sn30笼合物提供较好的理论指导。 展开更多
关键词 第一性原理 笼合物 热电材料 电子结构 结构稳定性
下载PDF
Mg-Er金属间化合物稳定性与电子结构的第一性原理研究 被引量:8
18
作者 王文静 刘子利 +2 位作者 刘希琴 张志东 王渠东 《中国有色金属学报》 EI CAS CSCD 北大核心 2014年第2期343-350,共8页
采用基于密度泛函理论的第一性原理赝势方法优化Mg-Er合金体系中MgEr、Mg2Er和Mg24Er5这3种金属间化合物的结构模型,通过形成热、结合能和电子结构的计算分析了化合物的稳定性与其晶体结构的内在联系。结果表明:3种Mg-Er金属间化合物的... 采用基于密度泛函理论的第一性原理赝势方法优化Mg-Er合金体系中MgEr、Mg2Er和Mg24Er5这3种金属间化合物的结构模型,通过形成热、结合能和电子结构的计算分析了化合物的稳定性与其晶体结构的内在联系。结果表明:3种Mg-Er金属间化合物的形成热和结合能均为负值,化合物的形成能力和稳定性均随着化合物中Er含量的降低而降低。在费米能级低能级区域,Mg的3s、2p轨道与Er的4f、5d轨道发生重叠,产生了轨道杂化;在费米能级高能级区域,Mg的2p轨道与Er的5d轨道也存在少量的杂化。随着化合物中Er含量的降低,化合物中平均每个原子在费米能级低能级处的成键电子数减少,化合物的稳定性降低。在Mg、Er原子周围均有大量的电荷存在,呈典型的金属键特征,Mg、Er之间的电子云只有部分重叠,交界处电荷的畸变不大。Mg-Er金属间化合物的价键结合具有金属键和共价键两重性,其中金属键占主导地位。Mg、Er原子的电荷转移量随化合物中Er含量降低而减少,化合物的共价键性降低,稳定性下降。 展开更多
关键词 Mg-Er金属间化合物 第一性原理 稳定性 电子结构
下载PDF
Ti,Cr,Al和B合金化元素对α-Nb_5Si_3力学性能和电子结构的影响 被引量:7
19
作者 邹爱华 徐江 黄豪杰 《物理化学学报》 SCIE CAS CSCD 北大核心 2014年第2期289-296,共8页
采用基于密度泛函理论(DFT)的第一性原理方法,通过比较形成能(Eform)、价电子浓度(VEC)、弹性常数(Cij)、剪切模量(G)与体模量(B)的比值(G/B)以及派-纳力(τP-N)等参量的变化,研究了Ti、Cr、Al和B合金化对D81结构的α-Nb5Si3结构稳定性... 采用基于密度泛函理论(DFT)的第一性原理方法,通过比较形成能(Eform)、价电子浓度(VEC)、弹性常数(Cij)、剪切模量(G)与体模量(B)的比值(G/B)以及派-纳力(τP-N)等参量的变化,研究了Ti、Cr、Al和B合金化对D81结构的α-Nb5Si3结构稳定性和力学性能的影响.研究表明:合金化元素Ti、Cr、Al和B分别优先占据α-Nb5Si3中Nb4c、Nb4c、Si4a和Si8h位置;添加不同含量合金化元素的α-Nb5Si3仍保持稳定的D81结构;Ti、Al和B合金化使α-Nb5Si3的脆性增加,而随着Cr含量的增加,α-Nb5Si3的韧性逐渐增强.此外,态密度(DOS)和Mulliken布居等电子结构的计算结果表明:Ti、Al和B合金化导致α-Nb5Si3脆性增加的主要原因是提高了共价键的强度;而Cr合金化的增韧作用主要来源于共价键数量的减少和强度的削弱,以及更多的反键态被占据. 展开更多
关键词 第一性原理 铌硅化合物 结构稳定性 脆性 电子结构
下载PDF
Ti-Ni金属间化合物电子结构与力学性质的第一性原理计算 被引量:8
20
作者 王鹏 李军 +5 位作者 林崇智 杨柳 彭琳 王莹 肖聪 陈敬超 《中国有色金属学报》 EI CAS CSCD 北大核心 2016年第12期2546-2554,共9页
采用基于密度泛函理论(DFT)的第一性原理赝势平面波方法,计算Ti-Ni合金系中TiNi、Ti_2Ni和TiNi_3金属间化合物的平衡晶格常数、生成焓、内聚能、力学性质、德拜温度和电子结构。计算结果表明:TiNi、Ti_2Ni和TiNi_3金属间化合物均具有热... 采用基于密度泛函理论(DFT)的第一性原理赝势平面波方法,计算Ti-Ni合金系中TiNi、Ti_2Ni和TiNi_3金属间化合物的平衡晶格常数、生成焓、内聚能、力学性质、德拜温度和电子结构。计算结果表明:TiNi、Ti_2Ni和TiNi_3金属间化合物均具有热力学稳定性且容易合金化生成,合金形成能力由强到弱的排序为TiNi_3、TiNi、Ti_2Ni;3种金属间化合物的晶体结构在能量上和力学上都是稳定的,结构稳定性由大到小排序依次为Ti_2Ni、TiNi、TiNi_3;TiNi和Ti_2Ni为延性相(延展性Ti_2Ni大于TiNi的),TiNi_3的延展性较差;3d电子是TiNi、Ti_2Ni和TiNi_3金属间化合物的最主要的成键电子,在这3种金属间化合物中,随着Ni相对含量的增加,平均成键电子数增多,共价键的比例增加,化学键的强度增强,金属性减弱,从而使得其弹性模量、硬度和德拜温度均逐渐升高。 展开更多
关键词 TI-NI 金属间化合物 电子结构 力学性质 第一性原理
下载PDF
上一页 1 2 6 下一页 到第
使用帮助 返回顶部