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Intrinsic homogeneous linewidth and broadening mechanisms of excitons in monolayer transition metal dichalcogenides

G. Moody ; C. Kavir Dass ; K. Hao ; C. H. Chen ; L. J. Li ; A. Singh ; K. Tran ; G. Clark ; X. Xu ; G. Berghäuser ; Ermin Malic (Institutionen för teknisk fysik, Kondenserade materiens teori) ; A. Knorr ; X. Li
Nature Communications (2041-1723). Vol. 6 (2015), p. Art. no. 8315.
[Artikel, refereegranskad vetenskaplig]

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.

Denna post skapades 2015-10-08. Senast ändrad 2016-01-20.
CPL Pubid: 223823


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Institutioner (Chalmers)

Institutionen för teknisk fysik, Kondenserade materiens teori (1900-2015)


Metallurgi och metalliska material

Chalmers infrastruktur



Denna publikation är ett resultat av följande projekt:

Graphene-Based Revolutions in ICT And Beyond (GRAPHENE) (EC/FP7/604391)