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.
WSe 2
exciton
van der Waals heterostructure
transition metal dichalcogenides
MoSe 2
Author
Junho Choi
The University of Texas at Austin
Jacob Embley
The University of Texas at Austin
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
The University of Texas at Austin
Long Yuan
Purdue University
Woo Young Yoon
The University of Texas at Austin
Takashi Taniguchi
National Institute for Materials Science (NIMS)
Kenji Watanabe
National Institute for Materials Science (NIMS)
Keiji Ueno
Saitama University
Emanuel Tutuc
The University of Texas at Austin
Samuel Brem
Philipps University Marburg
Ermin Malic
Chalmers, Physics, Condensed Matter and Materials Theory
Philipps University Marburg
Xiaoqin Li
The University of Texas at Austin
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
Atom and Molecular Physics and Optics
Fusion, Plasma and Space Physics
Condensed Matter Physics
DOI
10.1021/acs.nanolett.3c00678