Momentum resolved ground/excited states and the ultra-fast excited state dynamics of monolayer MoS<sub>2</sub>

ORAL

Abstract

The emergence of transition metal dichalcogenides (TMD) as crystalline atomically thin semiconductors has created a tremendous amount of scientific and technological interest. Many novel device concepts have been proposed and realized. Nonetheless, progress in k-space investigations of ground/excited state electronic structures has been slow due to the challenge to create large scale, laterally homogeneous samples. Taking advantage of recent advancements in chemical vapor deposition, here we create a wafer-size MoS2 monolayer with well-aligned lateral orientation. The ground state and excited state electronic structures are probed using scanning tunneling spectroscopy (STS), angle-resolved photoemission (ARPES) and time-resolved (tr-)ARPES. In addition to mapping out the momentum-space quasiparticle band structure in the valence and conduction bands, we unveil ultrafast excited state dynamics, including inter- and intra-valley carrier scattering and a rapid downward energy shift by ~ 0.2eV lower than the initial free carrier state at sigma point.

*NSF-MRSEC DMR-1720595, NSF-DMR 1808751, Welch foundation F-1672, US Airforce FA2386-18-1-4097, DOE DE-AC02-05-CH11231, MOST-107-2112-M-009-024-MY3 and MOST-108-2119-M-009-011-MY3

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Presenters

  • Woojoo Lee

    • Physics, University of Texas at Austin
    • Department of Physics, The University of Texas at Austin

Authors

  • Woojoo Lee

    • Physics, University of Texas at Austin
    • Department of Physics, The University of Texas at Austin

  • Yi Lin

    • Materials Sciences Division, Lawrence Berkeley National Laboratory
    • Lawrence Berkeley National Laboratory
    • Materials Science Division, Lawrence Berkeley National Laboratory

  • Li-Syuan Lu

    • Department of Electrophysics, National Chiao Tung University
    • Electrophysics, National Chiao Tung University

  • Wei-Chen Chueh

    • Electrophysics, National Chiao Tung University

  • Mengke Liu

    • Physics, University of Texas at Austin
    • University of Texas at Austin

  • Xiaoqin (Elaine) Li

    • University of Texas at Austin
    • Physics, University of Texas at Austin
    • Department of Physics, University of Texas at Austin
    • U.T. Austin
    • Department of Physics, The University of Texas at Austin
    • Department of Physics, Center of Complex Quantum Systems, University of Texas at Austin

  • Wen-Hao Chang

    • Department of Electrophysics, National Chiao Tung University
    • Electrophysics, National Chiao Tung University
    • Natl Chiao Tung Univ

  • Robert A Kaindl

    • Materials Sciences Division, Lawrence Berkeley National Laboratory
    • Lawrence Berkeley National Laboratory
    • Department of Physics, Arizona State University
    • Physics, Arizona State University

  • Chih-Kang Shih

    • Physics, University of Texas at Austin
    • University of Texas at Austin
    • Department of Physics, The University of Texas at Austin