imprint:
Springer Science and Business Media LLC, 2019
Published in:Communications Physics
Language:
English
DOI:
10.1038/s42005-019-0122-z
ISSN:
2399-3650
Origination:
Footnote:
Description:
<jats:title>Abstract</jats:title><jats:p>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 MoSe<jats:sub>2</jats:sub>–WSe<jats:sub>2</jats:sub> heterostructure. We identify tunneling of holes from MoSe<jats:sub>2</jats:sub> to WSe<jats:sub>2</jats:sub> 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.</jats:p>