Charge density wave and weak Kondo effect in a Dirac semimetal CeSbTe

作者：Peng Li,BaiJiang Lv,Yuan Fang,Wei Guo,ZhongZheng Wu,Yi Wu,DaWei Shen,YueFeng Nie,Luca Petaccia,Chao Cao,Zhu-An Xu,Yang Liu

摘要：Using angle-resolved photoemission spectroscopy(ARPES) and low-energy electron diffraction(LEED), together with densityfunctional theory(DFT) calculation, we report the formation of charge density wave(CDW) and its interplay with the Kondo effect and topological states in CeSbTe. The observed Fermi surface(FS) exhibits parallel segments that can be well connected by the observed CDWordering vector, indicating that the CDWorder is driven by the electron-phonon coupling(EPC) as a result of the nested FS. The CDW gap is large(~0.3 eV) and momentum-dependent, which naturally explains the robust CDWorder up to high temperatures. The gap opening leads to a reduced density of states(DOS) near the Fermi level(EF), which correspondingly suppresses the many-body Kondo effect, leading to very localized 4 f electrons at 20 K and above. The topological Dirac cone at the X point is found to remain gapless inside the CDW phase. Our results provide evidence for the competition between CDWand the Kondo effect in a Kondo lattice system. The robust CDWorder in CeSbTe and related compounds provide an opportunity to search for the long-sought-after axionic insulator.

发文机构：Zhejiang Province Key Laboratory of Quantum Technology and Device Center for Correlated Matter National Laboratory of Solid State Microstructures State Key Laboratory of Functional Materials for Informatics and Center for Excellence in Superconducting Electronics Collaborative Innovation Center of Advanced Microstructures Elettra Sincrotrone Trieste Department of Physics

关键词：chargedensitywaveKondoeffectDiracsemimetal

分类号： O46[理学—电子物理学]