Ultrafast dynamics in monolayer transition metal dichalcogenides: Interplay of dark excitons, phonons, and intervalley exchange
Artikel i vetenskaplig tidskrift, 2019

Understanding the ultrafast coupling and relaxation mechanisms between valleys in transition metal dichalcogenide semiconductors is of crucial interest for future valleytronic devices. Recent ultrafast pump-probe experiments showed an unintuitive significant bleaching at the excitonic B transition after optical excitation of the energetically lower excitonic A transition. Here, we present a possible microscopic explanation for this surprising effect. It is based on the joint action of exchange coupling and phonon-mediated thermalization into dark exciton states and does not involve a population of the B exciton. Our work demonstrates how intra- and intervalley coupling on a femtosecond timescale governs the optical valley response of 2D semiconductors.

Författare

M. Selig

Technische Universität Berlin

Florian Katsch

Technische Universität Berlin

Robert Schmidt

Universität Münster

S. M. de Vasconcellos

Universität Münster

R. Bratschitsch

Universität Münster

Ermin Malic

Chalmers, Fysik, Kondenserade materiens teori

A. Knorr

Technische Universität Berlin

Physical Review Research

26431564 (ISSN)

Vol. 1 2 022007

Ämneskategorier

Atom- och molekylfysik och optik

Annan fysik

Den kondenserade materiens fysik

DOI

10.1103/PhysRevResearch.1.022007

Mer information

Senast uppdaterat

2021-10-14