Tunable magneto-optical properties in MoS2 via defect-induced exciton transitions

作     者：Tomer Amit Daniel Hernangómez-Pérez Galit Cohen Diana Y. Qiu Sivan Refaely-Abramson 

作者机构：Department of Molecular Chemistry and Materials Science Weizmann Institute of Science Rehovot 7610001 Israel Department of Mechanical Engineering and Materials Science Yale University New Haven Connecticut 06511 USA 

出 版 物：《Physical Review B》 (Phys. Rev. B)

年 卷 期：2022年第106卷第16期

页      面：L161407-L161407页

核心收录：

基　　金：U.S. Department of Energy, USDOE Office of Science, SC, (DE-AC05-00OR22725) Basic Energy Sciences, BES, (DE-SC0021965) Minerva Foundation 

主　　题：Defects Excitons Magneto-optics Transition metal dichalcogenides Ab initio calculations Many-body techniques 

摘      要：The presence of chalcogen vacancies in monolayer transition metal dichalcogenides (TMDs) leads to excitons with mixed localized-delocalized character and to reduced valley selectivity. Recent experimental advances in defect design in TMDs allow for a close examination of such mixed exciton states as a function of their degree of circular polarization under external magnetic fields, revealing strongly varying defect-induced magnetic properties. A theoretical understanding of these observations and their physical origins demands a predictive, structure-sensitive theory. In this work, we study the effect of chalcogen vacancies on the exciton magnetic properties in monolayer MoS2. Using many-body perturbation theory, we show how the complex excitonic picture associated with the presence of defects—with reduced valley and spin selectivity due to hybridized electron-hole transitions—leads to a structurally controllable exciton magnetic response. We find a variety of g-factors with changing magnitudes and sign depending on the exciton energy and character. Our findings suggest a pathway to tune the nature of the excitons—and by that their magneto-optical properties—through defect architecture.