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Theory of coherent pump–probe spectroscopy in monolayer transition metal dichalcogenides

Theory of coherent pump–probe spectroscopy in monolayer transition metal dichalcogenides

Authors :
Malte Selig
Florian Katsch
Andreas Knorr
Source :
2D Materials. 7:015021
Publication Year :
2019
Publisher :
IOP Publishing, 2019.

Abstract

A valley-selective circular dichroism and a pronounced spin-valley locking in monolayer transition metal dichalcogenides (TMDCs) enable the investigation of new many-body physics revealed in the ultrafast nonlinear optical response of these atomically thin materials. While this topic is experimentally well studied in pump-probe spectroscopy, only a fragmented theoretical understanding is available due to the complexity and multitude of occurring effects. Here, a microscopic approach is presented to describe the ultrafast pump-probe response of monolayer TMDCs in the coherent limit. We focus on close to band edge excitations dominated by strongly correlated, bound electron-hole pairs, namely excitonic excitations. The approach includes Hartree–Fock and correlation effects up to two excitonic excitations known from conventional semiconductors as well as TMDC typical Coulomb mechanisms such as intra- and intervalley excitation and charge transfer. The investigated coherent limit is able to explain different signatures observed in ultrafast pump-probe spectroscopy for temporal pump-probe overlap within one consistent formalism dominated by excitons, biexcitons, and exciton-exciton scattering states.

Details

ISSN :
20531583
Volume :
7
Database :
OpenAIRE
Journal :
2D Materials
Accession number :
edsair.doi...........8807a617719b34fea99075c385248213
Full Text :
https://doi.org/10.1088/2053-1583/ab5407