Anisotropic exciton diffusion in atomically-thin semiconductors
Journal article, 2022

Energy transport processes are critical for the efficiency of many optoelectronic applications. The energy transport in technologically promising transition metal dichalcogenides is determined by exciton diffusion, which strongly depends on the underlying excitonic and phononic dispersion. Based on a fully microscopic theory we demonstrate that the valley-exchange interaction leads to an enhanced exciton diffusion due to the emergence of a linear excitonic dispersion and the resulting decreased exciton-phonon scattering. Interestingly, we find that the application of a uniaxial strain can drastically boost the diffusion speed and even give rise to a pronounced anisotropic diffusion, which persists up to room temperature. We reveal that this behaviour originates from the highly anisotropic exciton dispersion in the presence of strain, displaying parabolic and linear behaviour perpendicular and parallel to the strain direction, respectively. Our work demonstrates the possibility to control the speed and direction of exciton diffusion via strain and dielectric engineering. This opens avenues for more efficient and exotic optoelectronic applications of atomically thin materials.

strain

TMD

anisotropic

exciton

exchange

semiconductors

diffusion

Author

Joshua Thompson

Philipps University Marburg

Chalmers, Physics, Condensed Matter and Materials Theory

Samuel Brem

Philipps University Marburg

Marne Verjans

Chalmers, Physics, Condensed Matter and Materials Theory

Robert Schmidt

University of Münster

Steffen Michaelis de Vasconcellos

University of Münster

Rudolf Bratschitsch

University of Münster

Ermin Malic

Chalmers, Physics, Condensed Matter and Materials Theory

Philipps University Marburg

2D-Tech

2D Materials

2053-1583 (eISSN)

Vol. 9 2 025008

2D material-based technology for industrial applications (2D-TECH)

GKN Aerospace Sweden (2D-tech), 2021-01-01 -- 2024-12-31.

VINNOVA (2019-00068), 2020-05-01 -- 2024-12-31.

Subject Categories

Physical Chemistry

Condensed Matter Physics

DOI

10.1088/2053-1583/ac4d13

More information

Latest update

2/29/2024