Revealing excitonic processes and chemical bonding in MoS2 by x-ray spectroscopy

作     者：J. C. Woicik C. Weiland A. K. Rumaiz M. Brumbach N. F. Quackenbush J. M. Ablett E. L. Shirley 

作者机构：Materials Measurement Science Division Material Measurement Laboratory National Institute of Standards and Technology Gaithersburg Maryland 20899 USA National Synchrotron Light Source II Brookhaven National Laboratory Upton New York 11973 USA Materials Characterization Department Sandia National Laboratories Albuquerque New Mexico 87185 USA Synchrotron SOLEIL L’Orme des Merisiers Saint-Aubin BP 48 91192 Gif-sur-Yvette Cedex France Sensor Science Division Physical Measurement Laboratory National Institute of Standards and Technology Gaithersburg Maryland 20899 USA 

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

年 卷 期：2018年第98卷第11期

页      面：115149-115149页

核心收录：

学科分类：0809[工学-电子科学与技术（可授工学、理学学位）] 07[理学] 070205[理学-凝聚态物理] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0702[理学-物理学] 

基　　金：Office of Basic Energy Sciences US Department of Energy 

主　　题：Bethe-Salpeter equation Chemical bonding Electronic structure Transition metal dichalcogenides X-ray absorption spectroscopy 

摘      要：Electron core-hole processes at absorption edges sport several signatures, primarily in the form of bound states and/or excitonic enhancement. Through analysis of the resonant-Raman Auger effect for the two-dimensional transition-metal dichalcogenide MoS2, we demonstrate that these effects have significant manifestations at the S K edge. We characterize two asymmetric excitonically enhanced edges: one at the fundamental band edge and one several electron volts above it following a second band gap that lies entirely within the unoccupied states, with the latter revealing an anomalous postcollision interaction effect. Our interpretation is supported by comparison of both the photoemission valence-band spectrum and the S K-edge x-ray-absorption spectrum with electronic structure calculations and an ab initio solution of the Bethe-Salpeter equation that accurately accounts for the electron-core-hole interaction.