Interlayer exciton dynamics in van der Waals heterostructures
Journal article, 2019

Atomically thin transition metal dichalcogenides can be stacked to van der Waals heterostructures enabling the design of new materials with tailored properties. The strong Coulomb interaction gives rise to interlayer excitons, where electrons and holes are spatially separated in different layers. In this work, we reveal the time- and momentum-dependent elementary processes behind the formation, thermalization and photoemission of interlayer excitons for the exemplary MoSe2-WSe2 heterostructure. We identify tunneling of holes from MoSe2 to WSe2 on a ps timescale as the crucial process for interlayer exciton formation. We also predict a drastic reduction of the formation time as a function of the interlayer energy offset suggesting that interlayer excitons can be externally tuned. Finally, we explain the experimental observation of a dominant photoluminescence from interlayer excitons despite the vanishingly small oscillator strength as a consequence of huge interlayer exciton occupations at low temperatures.

Author

Simon Ovesen

Chalmers, Physics, Condensed Matter Theory

Samuel Brem

Chalmers, Physics, Condensed Matter Theory

Christopher Linderälv

Chalmers, Physics, Materials and Surface Theory

Mikael Juhani Kuisma

Chalmers, Physics, Materials and Surface Theory

Tobias Korn

University of Rostock

Paul Erhart

Chalmers, Physics, Materials and Surface Theory

Malte Selig

Technische Universität Berlin

Ermin Malic

Chalmers, Physics, Condensed Matter Theory

Communications Physics

2399-3650 (ISSN)

Vol. 2 23

Subject Categories

Materials Chemistry

Other Physics Topics

Condensed Matter Physics

DOI

10.1038/s42005-019-0122-z

More information

Latest update

5/6/2019 1