Exciton fine structure in twisted transition metal dichalcogenide heterostructures  

作　　者：Sudipta Kundu Tomer Amit H.R.Krishnamurthy Manish Jain Sivan Refaely-Abramson 

机构地区：[1]Centre for Condensed Matter Theory,Department of Physics,Indian Institute of Science,Bangalore 560012,India [2]Department of Molecular Chemistry and Materials Science,Weizmann Institute of Science,Rehovot 7610001,Israel [3]Present address:Department of Materials Science and Engineering,Stanford University,Stanford,CA 94305,USA

出　　处：《npj Computational Materials》2023年第1期417-423,共7页计算材料学（英文）

基　　金：The project has received further funding from the European Research Council(ERC),Grant agreement No.101041159;an Israel Science Foundation Grant No.1208/19.M.J.and H.R.K.gratefully acknowledge the National Supercomputing Mission of the Department of Science and Technology,India,and the Science and Engineering Research Board of the Department of Science and Technology,India,for financial support under Grants No.DST/NSM/R&D_HPC_Applications/2021/23 and No.SB/DF/005/2017,respectively;Computational resources were provided by the Oak Ridge Leadership Computing Facility through the Innovative and Novel Computational Impact on Theory and Experiment(INCITE)program,which is a DOE Office of Science User Facility supported under Contract No.DE-AC05-00OR22725;Supercomputer Education and Research Center at Indian Institute of Science;the ChemFarm cluster at the Weizmann Institute of Science.

摘　　要：Moirésuperlattices of transition metal dichalcogenide(TMD)heterostructures give rise to rich excitonic phenomena associated with the interlayer twist angle.Theoretical calculations of excitons in such systems are typically based on model moirépotentials that mitigate the computational cost.However,predictive understanding of the electron-hole coupling dominating the excitations is crucial to realize the twist-induced modifications of the optical selection rules.In this work,we use many-body perturbation theory to evaluate the relation between twist angle and exciton properties in TMD heterostructures.We present an approach for unfolding excitonic states from the moiréBrillouin zone onto the separate-layer ones.Applying this method to a large-angle twisted MoS^(2)/MoSe^(2) bilayer,we find that the optical spectrum is dominated by mixed electron–hole transitions with different momenta in the separate monolayers,leading to unexpected hybridization between interlayer and intralayer excitons.Our findings offer a design pathway for exciton layer-localization in TMD heterostructures.

关 键 词：TWISTED TWIST TRANSITION 

分 类 号：TB33[一般工业技术—材料科学与工程]