Anisotropic exciton diffusion in atomically-thin semiconductors
Artikel i vetenskaplig tidskrift, 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.

anisotropic

exchange

TMD

strain

semiconductors

exciton

diffusion

Författare

Joshua Thompson

Chalmers, Fysik, Kondenserad materie- och materialteori

Philipps-Universität Marburg

Samuel Brem

Philipps-Universität Marburg

Marne Verjans

Chalmers, Fysik, Kondenserad materie- och materialteori

Robert Schmidt

Universität Münster

Steffen Michaelis de Vasconcellos

Universität Münster

Rudolf Bratschitsch

Universität Münster

Ermin Malic

Philipps-Universität Marburg

Chalmers, Fysik, Kondenserad materie- och materialteori

2D Materials

2053-1583 (eISSN)

Vol. 9 2 025008

Ämneskategorier

Fysikalisk kemi

Den kondenserade materiens fysik

DOI

10.1088/2053-1583/ac4d13

Mer information

Senast uppdaterat

2022-02-17