Development of the Band Calculation based on the Dynamical Mean Field Theory

基于动态平均场理论的能带计算的发展

基本信息

批准号：
14340108
负责人：
SAKAI Osamu
金额：
$ 6.91万
依托单位：
Tokyo Metropolitan University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

The main purposes of this project were to development the band calculation method based on the dynamical mean field theory for general use, and to study related phenomena of strongly correlated electron systems.(1) A method named as NCAf2v' was developed to solve the auxiliary single site Kondo problem. This enables us to include the correct exchange process through the f1-f2 valence fluctuation along with the f1-f0 fluctuation. The usual NCA method restricts the latter one.(2) The band calculation program was developed by the combination of the LMTO and the NCAf2v' method. The spin-orbit (SO) splitting and the crystalline filed splitting (CF) of the self energy were included in the calculation.(3) The method was applied to Ce metal and CeSb.In the y-phase of Ce metal, the CF splitting energy is larger than the Kondo temperature, while in the a-phase the Kondo temperature is larger than the CF splitting. The SO side peak becomes conspicuous in photo-emission-spectra similarly to the experimental results.In CeSb two peaks structure of PBS was reproduced. A rather higher Kondo temperature is expected because a small peak appears at the Fermi energy in the effective hybridization, which is caused by the strongly correlated 4f band.The magnetic alloy problem of 3d metals was also studied. The Curie temperature id decreased by the correlation type fluctuation effects.The optical and thermoelectric effects of Kondo insulator materials such as YbB12 were studied based on the tight biding model which reproduces the main features of band structures.The dynamical excitation of multipolar ordering systems such as PrOs4Sb12 was also studied.

该项目的主要目的是开发基于一般用途的动力学平均场理论的频带计算方法，并研究强相关的电子系统的相关现象。（1）开发了一种称为NCAF2V'的方法来解决辅助单位位点近调问题。这使我们能够通过F1-F2价波动以及F1-F0波动来包括正确的交换过程。通常的NCA方法限制了后者。（2）频段计算程序是通过LMTO和NCAF2V方法的组合开发的。计算中包括自旋轨道（SO）分裂和自我能量的晶体分裂（CF）。（3）将方法应用于CE金属和CESB。在CE金属的Y期中，CF分裂能量大于近相比温度，而在A型中，Kondo温度比CF分裂更大。与实验结果相似。在光发射 - 光谱中，SO侧峰变得明显。在CESB中，PBS的两个峰结构被复制。预期的北极温度相当较高，因为在有效杂交中，在费米能量上出现了一个小峰，这是由密切相关的4F带引起的。还研究了3D金属的磁合金问题。根据相关类型的波动效应，居里温度ID降低了。基于紧密的划船模型，还研究了带状结构的主要特征的近托绝缘子材料（例如YBB12）的光电和热电效应。