Theory of exciton dynamics in time-resolved ARPES: Intra- and intervalley scattering in two-dimensional semiconductors
Journal article, 2019

Time- and angle-resolved photoemission spectroscopy (trARPES) is a powerful spectroscopic method to measure the ultrafast electron dynamics directly in momentum space. However, band gap materials with exceptionally strong Coulomb interaction such as monolayer transition-metal dichalcogenides exhibit tightly bound excitons, which dominate their optical properties. This raises the question of whether excitons, in particular their formation and relaxation dynamics, can be detected in photoemissions. Here, we develop a fully microscopic theory of the temporal dynamics of excitonic time- and angle-resolved photoemission with a particular focus on the phonon-mediated thermalization of optically excited excitons to momentum-forbidden dark exciton states. We find that trARPES is able to probe the ultrafast exciton formation and relaxation throughout the Brillouin zone.

Author

Dominik Christiansen

Technische Universität Berlin

Malte Selig

Technische Universität Berlin

Ermin Malic

Chalmers, Physics, Condensed Matter Theory

Ralph Ernstorfei

Max Planck Society

Andreas Knorr

Technische Universität Berlin

Physical Review B

2469-9950 (ISSN) 2469-9969 (eISSN)

Vol. 100 20 205401

Subject Categories

Atom and Molecular Physics and Optics

Other Physics Topics

Condensed Matter Physics

DOI

10.1103/PhysRevB.100.205401

More information

Latest update

1/13/2020