Intrinsic homogeneous linewidth and broadening mechanisms of excitons in monolayer transition metal dichalcogenides
Artikel i vetenskaplig tidskrift, 2015

The band-edge optical response of transition metal dichalcogenides, an emerging class of atomically thin semiconductors, is dominated by tightly bound excitons localized at the corners of the Brillouin zone (valley excitons). A fundamental yet unknown property of valley excitons in these materials is the intrinsic homogeneous linewidth, which reflects irreversible quantum dissipation arising from system (exciton) and bath (vacuum and other quasiparticles) interactions and determines the timescale during which excitons can be coherently manipulated. Here we use optical two-dimensional Fourier transform spectroscopy to measure the exciton homogeneous linewidth in monolayer tungsten diselenide (WSe 2). The homogeneous linewidth is found to be nearly two orders of magnitude narrower than the inhomogeneous width at low temperatures. We evaluate quantitatively the role of exciton-exciton and exciton-phonon interactions and population relaxation as linewidth broadening mechanisms. The key insights reported here - strong many-body effects and intrinsically rapid radiative recombination - are expected to be ubiquitous in atomically thin semiconductors.

Författare

G. Moody

The University of Texas at Austin

National Institute of Standards and Technology

C. Kavir Dass

The University of Texas at Austin

K. Hao

The University of Texas at Austin

C. H. Chen

Feng Chia University

L. J. Li

King Abdullah University of Science and Technology (KAUST)

A. Singh

The University of Texas at Austin

K. Tran

The University of Texas at Austin

G. Clark

University of Washington

X. Xu

University of Washington

Gunnar Berghäuser

Technische Universität Berlin

Ermin Malic

Chalmers, Teknisk fysik, Kondenserade materiens teori

A. Knorr

Technische Universität Berlin

X. Li

The University of Texas at Austin

Nature Communications

2041-1723 (ISSN)

Vol. 6 Art. no. 8315- 8315

Graphene-Based Revolutions in ICT And Beyond (Graphene Flagship)

Europeiska kommissionen (FP7), 2013-10-01 -- 2016-03-31.

Ämneskategorier

Fysik

Metallurgi och metalliska material

DOI

10.1038/ncomms9315

PubMed

26382305