Fermi Pressure and Coulomb Repulsion Driven Rapid Hot Plasma Expansion in a van der Waals Heterostructure
Journal article, 2023
Transition metal dichalcogenide heterostructures provide a versatile platform to explore electronic and excitonic phases. As the excitation density exceeds the critical Mott density, interlayer excitons are ionized into an electron-hole plasma phase. The transport of the highly non-equilibrium plasma is relevant for high-power optoelectronic devices but has not been carefully investigated previously. Here, we employ spatially resolved pump-probe microscopy to investigate the spatial-temporal dynamics of interlayer excitons and hot-plasma phase in a MoSe2/WSe2 twisted bilayer. At the excitation density of ∼1014 cm-2, well exceeding the Mott density, we find a surprisingly rapid initial expansion of hot plasma to a few microns away from the excitation source within ∼0.2 ps. Microscopic theory reveals that this rapid expansion is mainly driven by Fermi pressure and Coulomb repulsion, while the hot carrier effect has only a minor effect in the plasma phase.
van der Waals heterostructure
MoSe 2
exciton
WSe 2
transition metal dichalcogenides
Author
Junho Choi
University of Texas
Jacob Embley
University of Texas
Daria D. Blach
Purdue University
Raul Perea Causin
Chalmers, Physics, Condensed Matter and Materials Theory
Daniel Erkensten
Chalmers, Physics, Condensed Matter and Materials Theory
Dong Seob Kim
University of Texas
Long Yuan
Purdue University
Woo Young Yoon
University of Texas
Takashi Taniguchi
National Institute for Materials Science (NIMS)
Kenji Watanabe
National Institute for Materials Science (NIMS)
Keiji Ueno
Saitama University
Emanuel Tutuc
University of Texas
Samuel Brem
Philipps University Marburg
Ermin Malic
Philipps University Marburg
Chalmers, Physics, Condensed Matter and Materials Theory
Xiaoqin Li
University of Texas
Libai Huang
Purdue University
Nano Letters
1530-6984 (ISSN) 1530-6992 (eISSN)
Vol. 23 10 4399-4405Graphene Core Project 3 (Graphene Flagship)
European Commission (EC) (EC/H2020/881603), 2020-04-01 -- 2023-03-31.
Subject Categories (SSIF 2011)
Atom and Molecular Physics and Optics
Fusion, Plasma and Space Physics
Condensed Matter Physics
DOI
10.1021/acs.nanolett.3c00678