Electronic structures and Mott state of epitaxial TaS_(2) monolayers  

作　　者：Qichao Tian Chi Ding Xiaodong Qiu Qinghao Meng Kaili Wang Fan Yu Yuyang Mu Can Wang Jian Sun Yi Zhang 

机构地区：[1]National Laboratory of Solid State Microstructure,School of Physics,Nanjing University,Nanjing 20093,China [2]Collaborative Innovation Center of Advanced Microstructures,Nanjing University,Nanjing 210093,China [3]School of Physics and Electronic Sciences,Changsha University of Science and Technology,Changsha 410114,China [4]Hefei National Laboratory,Hefei 230088,China

出　　处：《Science China(Physics,Mechanics & Astronomy)》2024年第5期91-97,共7页中国科学：物理学、力学、天文学（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant No.92165205);the Innovation Program for Quantum Science and Technology of China(Grant No.2021ZD0302803);the National Key Research and Development Program of China(Grant No.2018YFA0306800);the Program of High-Level Entrepreneurial and Innovative Talents Introduction of Jiangsu Province,China。

摘　　要：Layered material TaS2hosts multiple structural phases and exotic correlated quantum states,including charge density wave(CDW),superconductivity,quantum spin liquid,and Mott insulating state.Here,we synthesized TaS_(2)monolayers in H and T phases using the molecular beam epitaxial(MBE)method and studied their electronic structures via angle-resolved photoemission spectroscopy(ARPES).We found that the H phase TaS_(2)(H-TaS_(2))monolayer is metallic,with an energy band crossing the Fermi level.In contrast,the T phase TaS_(2)(T-TaS_(2))monolayer shows an insulated energy gap at the Fermi level,while the normal calculated band structure implies it should be metallic without any band gap.However,by considering Hubbard interaction potential U,further density functional theory(DFT)calculation suggests that monolayer T-TaS_(2)could be a CDW Mott insulator,and the DFT+U calculation matches well with the ARPES result.More significantly,the temperature-dependent ARPES result indicates that the CDW Mott state in the T-TaS_(2)monolayer is more robust than its bulk counterpart and can persist at room temperature.Our results reveal that the dimensional effect can enhance the CDW Mott state and provide valuable insights for further exploring the exotic properties of monolayer TaS2.

关 键 词：temperature MONOLAYER STATE 

分 类 号：O469[理学—凝聚态物理]