Hybridized intervalley moiré excitons and flat bands in twisted WSe(2)bilayers
Artikel i vetenskaplig tidskrift, 2020

The large surface-to-volume ratio in atomically thin 2D materials allows to efficiently tune their properties through modifications of their environment. Artificial stacking of two monolayers into a bilayer leads to an overlap of layer-localized wave functions giving rise to a twist angle-dependent hybridization of excitonic states. In this joint theory-experiment study, we demonstrate the impact of interlayer hybridization on bright and momentum-dark excitons in twisted WSe(2)bilayers. In particular, we show that the strong hybridization of electrons at the ? point leads to a drastic redshift of the momentum-dark K-? exciton, accompanied by the emergence of flat moire exciton bands at small twist angles. We directly compare theoretically predicted and experimentally measured optical spectra allowing us to identify photoluminescence signals stemming from phonon-assisted recombination of layer-hybridized dark excitons. Moreover, we predict the emergence of additional spectral features resulting from the moire potential of the twisted bilayer lattice.

Författare

Samuel Brem

Chalmers, Fysik, Kondenserad materie- och materialteori

Kai-Qiang Lin

Universität Regensburg

Roland Gillen

Friedrich-Alexander-Universität Erlangen Nurnberg (FAU)

Jonas M. Bauer

Universität Regensburg

Janina Maultzsch

Friedrich-Alexander-Universität Erlangen Nurnberg (FAU)

John M. Lupton

Universität Regensburg

Ermin Malic

Chalmers, Fysik, Kondenserad materie- och materialteori

Nanoscale

2040-3364 (ISSN)

Vol. 12 20 11088-11094

Ämneskategorier

Atom- och molekylfysik och optik

Annan fysik

Den kondenserade materiens fysik

DOI

10.1039/d0nr02160a

PubMed

32400821

Mer information

Senast uppdaterat

2020-10-12