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 4399-4405

Graphene 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

More information

Latest update

3/7/2024 9