Observation of Quantized Exciton Energies in Monolayer WSe2 under a Strong Magnetic Field

作     者：Tianmeng Wang Zhipeng Li Zhengguang Lu Yunmei Li Shengnan Miao Zhen Lian Yuze Meng Mark Blei Takashi Taniguchi Kenji Watanabe Sefaattin Tongay Wang Yao Dmitry Smirnov Chuanwei Zhang Su-Fei Shi 

作者机构：Department of Chemical and Biological Engineering Rensselaer Polytechnic Institute Troy New York 12180 USA National High Magnetic Field Lab Tallahassee Florida 32310 USA Department of Physics Florida State University Tallahassee Florida 32306 USA Department of Physics The University of Texas at Dallas Richardson Texas 75080 USA National Institute for Materials Science 1-1 Namiki Tsukuba 305-0044 Japan School for Engineering of Matter Transport and Energy Arizona State University Tempe Arizona 85287 USA Department of Physics and Center of Theoretical and Computational Physics University of Hong Kong Hong Kong China Department of Electrical Computer & Systems Engineering Rensselaer Polytechnic Institute Troy New York 12180 USA 

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

年 卷 期：2020年第10卷第2期

页      面：021024-021024页

核心收录：

学科分类：07[理学] 0702[理学-物理学] 

基　　金：State of Florida, (FA9550-16-1-0387, PHY-1806227) National Science Foundation, NSF, (1806227, 1838443, 1933214, NSF/DMR-1644779) National Science Foundation, NSF U.S. Department of Energy, USDOE, (DE-FG02-07ER46451) U.S. Department of Energy, USDOE American Cancer Society, ACS, (59957-DNI10) American Cancer Society, ACS Air Force Office of Scientific Research, AFOSR, (FA9550-18-1-0312) Air Force Office of Scientific Research, AFOSR Army Research Office, ARO, (W911NF-17-1-0128) Army Research Office, ARO Rensselaer Polytechnic Institute, RPI Empire State Development's Division of Science, Technology and Innovation, NYSTAR, (C150117, CMMI-1933214, DMR-1552220, DMR-1838443) Empire State Development's Division of Science, Technology and Innovation, NYSTAR National High Magnetic Field Laboratory, NHMFL Ministry of Education, Culture, Sports, Science and Technology, Monbusho Japan Science and Technology Agency, JST Core Research for Evolutional Science and Technology, CREST, (JPMJCR15F3) Core Research for Evolutional Science and Technology, CREST 

主　　题：Excitons Polarons 2-dimensional systems Transition metal dichalcogenides Reflectivity 

摘      要：Quantized energy levels are one of the hallmarks of quantum mechanics at the atomic level. The manifestation of quantization in macroscopic physical systems has showcased important quantum phenomena, such as quantized conductance in (fractional) quantum Hall effects and quantized vortices in superconductors. Here we report the first experimental observation of quantized exciton energies in a macroscopic system with strong Coulomb interaction, monolayer WSe2 crystal under a strong magnetic field. Employing helicity-resolved magnetoreflectance spectroscopy, we observe a striking ladder of plateaus as a function of the gate voltage for both exciton resonance in one valley and exciton-polariton branch in the opposite valley, thanks to the inter-Landau levels transitions governed by unique valley-selective selection rules. The observed quantized excitation energy level spacing sensitively depends on the doping level, indicating strong many-body effects. Our work will inspire the study of intriguing quantum phenomena originating from the interplay between Landau levels and many-body interactions in two-dimension monolayer crystals.