Coherent quantum dynamics of excitons in monolayer transition metal dichalcogenides
Paper i proceeding, 2016

Transition metal dichalcogenides (TMDs) have garnered considerable interest in recent years owing to their layer thickness-dependent optoelectronic properties. In monolayer TMDs, the large carrier effective masses, strong quantum confinement, and reduced dielectric screening lead to pronounced exciton resonances with remarkably large binding energies and coupled spin and valley degrees of freedom (valley excitons). Coherent control of valley excitons for atomically thin optoelectronics and valleytronics requires understanding and quantifying sources of exciton decoherence. In this work, we reveal how exciton-exciton and exciton-phonon scattering influence the coherent quantum dynamics of valley excitons in monolayer TMDs, specifically tungsten diselenide (WSe2), using two-dimensional coherent spectroscopy. Excitation-density and temperature dependent measurements of the homogeneous linewidth (inversely proportional to the optical coherence time) reveal that exciton-exciton and exciton-phonon interactions are significantly stronger compared to quasi-2D quantum wells and 3D bulk materials. The residual homogeneous linewidth extrapolated to zero excitation density and temperature is 1:6 meV (equivalent to a coherence time of 0.4 ps), which is limited only by the population recombination lifetime in this sample. (c) (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only

mono layer

Multi-Dimensional Coherent Spectroscopy

crystals

valley polarization

Homogeneous Linewidth

photoluminescence

mos2

Exciton

spin

semiconductor

molybdenum-disulfide

lifetimes

wse2

Transition Metal Dichalcogenides

Författare

G. Moody

National Institute of Standards and Technology

University of Texas at Austin

K. Hao

University of Texas at Austin

C. K. Dass

University of Texas at Austin

A. Singh

University of Texas at Austin

L. X. Xu

University of Texas at Austin

K. Tran

University of Texas at Austin

C. H. Chen

Feng Chia University

M. Y. Li

King Abdullah University of Science and Technology

L. J. Li

King Abdullah University of Science and Technology

G. Clark

University of Washington, Seattle

G. Berghäuser

Technische Universitat Berlin

Ermin Malic

Chalmers, Fysik, Kondenserade materiens teori

A. Knorr

Technische Universitat Berlin

X. D. Xu

University of Washington, Seattle

X. Q. Li

University of Texas at Austin

Proceedings of SPIE - The International Society for Optical Engineering

0277786X (ISSN) 1996756X (eISSN)

Vol. 9746 97461T

Ämneskategorier

Atom- och molekylfysik och optik

Elektroteknik och elektronik

DOI

10.1117/12.2209203

ISBN

978-1-62841-981-8