Electron-Correlation-Induced Charge Density Wave in FeGe  

作　　者：武琳 胡雅婷 樊东泽 王棣 万贤纲 Lin Wu;Yating Hu;Dongze Fan;Di Wang;Xiangang Wan(National Laboratory of Solid State Microstructures and School of Physics,Nanjing University,Nanjing 210093,China;Collaborative Innovation Center of Advanced Microstructures,Nanjing University,Nanjing 210093,China)

机构地区：[1]National Laboratory of Solid State Microstructures and School of Physics,Nanjing University,Nanjing 210093,China [2]Collaborative Innovation Center of Advanced Microstructures,Nanjing University,Nanjing 210093,China

出　　处：《Chinese Physics Letters》2023年第11期93-99,共7页中国物理快报（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.12188101,11834006,12004170,and 12334007);the National Key R&D Program of China(Grant No.2022YFA1403601);the Natural Science Foundation of Jiangsu Province(Grant No.BK20200326);the excellent programme in Nanjing University;supported by the New Cornerstone Science Foundation through the XPLORER PRIZE。

摘　　要：As the first magnetic kagome material to exhibit the charge density wave(CDW)order,FeGe has attracted much attention in recent research.Similar to AV_(3)Sb_(5)(A=K,Cs,Rb),FeGe exhibits the CDW pattern with an in-plane 2×2 structure and the existence of van Hove singularities near the Fermi level.However,sharply different from AV_(3)Sb_(5)which has phonon instability at M point,all the theoretically calculated phonon frequencies in FeGe remain positive.Based on first-principles calculations,we surprisingly find that the maximum of nesting function is at K point instead of M point.Two Fermi pockets with Fe-d_(xz)and Fe-d_(x^(2)-y^(2))/d_(xy)orbital characters have large contribution to the Fermi nesting,which evolve significantly with k_(z),indicating the highly three-dimensional(3D)feature of FeGe in contrast to AV_(3)Sb_(5).Considering the effect of local Coulomb interaction,we reveal that the instability at K point is significantly suppressed due to the sublattice interference mechanism.Meanwhile,the wave functions nested by vector M have many ingredients located at the same Fe site,thus the instability at M point is enhanced.This indicates that the electron correlation,rather than electron-phonon interaction,plays a key role in the CDW transition at M point.

关 键 词：MECHANISM PHONON FERMI 

分 类 号：O469[理学—凝聚态物理]