Computational Materials Science：From Ground States to Excitations in Solids2.pptVIP

下载本文档

7
0
约2.76千字
约 25页
2018-03-02 发布于江西
举报
版权申诉

Computational Materials Science：From Ground States to Excitations in Solids2.ppt

1、有哪些信誉好的足球投注网站（book118）网站文档一经付费（服务费），不意味着购买了该文档的版权，仅供个人/单位学习、研究之用，不得用于商业用途，未经授权，严禁复制、发行、汇编、翻译或者网络传播等，侵权必究。。
2、本站所有内容均由合作方或网友上传，本站不对文档的完整性、权威性及其观点立场正确性做任何保证或承诺！文档内容仅供研究参考，付费前请自行鉴别。如您付费，意味着您自己接受本站规则且自行承担风险，本站不退款、不进行额外附加服务；查看《如何避免下载的几个坑》。如果您已付费下载过本站文档，您可以点击这里二次下载。
3、如文档侵犯商业秘密、侵犯著作权、侵犯人身权等，请点击“版权申诉”（推荐），也可以打举报电话：400-050-0827(电话支持时间：9:00-18:30)。
4、该文档为VIP文档，如果想要下载，成为VIP会员后，下载免费。
5、成为VIP后，下载本文档将扣除1次下载权益。下载后，不支持退款、换文档。如有疑问请联系我们。
6、成为VIP后，您将拥有八大权益，权益包括：VIP文档下载权益、阅读免打扰、文档格式转换、高级专利检索、专属身份标志、高级客服、多端互通、版权登记。
7、VIP文档为合作方或网友上传，每下载1次，网站将根据用户上传文档的质量评分、类型等，对文档贡献者给予高额补贴、流量扶持。如果你也想贡献VIP文档。上传文档

Computational Materials Science：From Ground States to Excitations in Solids2

Simple metal (Free electron like): Na Fermi surface of Na Simple metal (Free electron like): Al Fermi Surface of Al Density of States: Al More complicated metal: Cu Fermi Surface of Cu More complicated metal: MgB2 Electron-phonon coupling in MgB2 Fermi Surface of MgB2 Semi-metal: Graphene Semi-metal: Graphene Semiconductor: Si Semiconductor: Si Magnetism: BCC Fe(DFT-GGA) Magnetism: HCP Co (DFT-GGA) Magnetism: CCP Ni(DFT-GGA) Magnetic Properties * Computational Materials Science: From Ground States to Excitations in Solids Peihong Zhang Department of Physics, University at Buffalo, SUNY July 20, 2009 USTC 2009 Summer School Outline Materials properties from first-principles: a hard problem Earlier efforts Density functional theory Local Density Approximation Success of DFT: Examples “Failure” of DFT Beyond DFT: LDA+U Beyond DFT: Quasiparticle and optical excitations in solids Electron-phonon coupling and superconductivity Materials design from first-principles: realizing the dream Total Energy, Cohesive Energy 0.28 0.27 Pd 0.42 0.45 Rh 0.50 0.49 Mo 0.56 0.55 Nb Experiment DFT-LDA Metal Total energy of atoms (Ry.) Cohesive energy (Ry.) Comparison between the highest occupied Kohn-Sham orbital energy and the ionization energy (in Ry) (a) Morrison, et al., 1995 Ionization Energy Structural Properties: Molecules Structural properties of diborane 1.19 1.33 97o 122o EXP 1.19 1.33 97o 122o DFT-GGA 1.20 1.32 98o 121o DFT-LDA d2 (?) d1 (?) b a Diborne (3c-2e bond) Lattice constant (a.u.) LDA predicts lattice constants to within 2%. Bulk modulus (Mbar) LDA predicts bulk modulus to within a few percents. Structural Properties Lattice constant a3 a1 a2 Structure: BCC Brillouin Zone Ef Structure: CCP (FCC) Brillouin Zone EF Note that if we plot the Fermi surface of Al in the extended zone scheme, it will still look like a sphere! Energy (eV) occupied empty In contrast, DOS for a metal does not show a gap near the Fermi energy Structure: CCP Brillouin Zone Energy (eV) d-b