Relation between electron mass enhancement and potential shape: Numerical analysis of two-site anharmonic Holstein-Hubbard model

International Conference on Strongly Correlated Electron Systems 2014

Matsuura, Tomoya^1 ; Hotta, Takashi^1,2

Department of Physics, Tokyo Metropolitan University, Tokyo

192-0397, Japan^1

Advanced Science Research Center, Japan Atomic Energy Agency, Ibaraki

319-1195, Japan^2

关键词: Cage structures;    Conduction electrons;    Electron mass;    Heavy electrons;    Holstein-hubbard model;    Potential region;    Single well;    Transition regions;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/592/1/012144/pdf
DOI  :  10.1088/1742-6596/592/1/012144

来源: IOP

【 摘 要 】

In order to promote our understanding on the emergence of magnetically robust heavy-electron state due to the interaction between conduction electrons and local anharmonic oscillations of guest atom in cage-structure materials, we investigate how the electron mass enhancement factor depends on the potential shape of the guest atom by analyzing numerically the two-site anharmonic Holstein-Hubbard model. It is found that the electron mass enhancement factor becomes maximum when the bottom of the potential becomes wide and flat. Such a potential is called a rattling type, which appears in the transition region between single-well and double-well types. Thus, the anharmonic oscillation in the rattling potential is considered to play a key role for the formation of the heavy-electron state in cage-structure compounds. We briefly discuss the reason why the electron mass enhancement factor becomes maximum in the rattling type potential region.