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HL: Fachverband Halbleiterphysik

HL 9: 2D Materials and Heterostructures: Interlayer Excitons

HL 9.4: Talk

Monday, March 18, 2024, 15:45–16:00, EW 201

Spin Relaxation of Interlayer Excitons in TMDC Heterostructures — •Henry Mittenzwey¹, Abhijeet Kumar², Kirill Bolotin², Malte Selig¹, and Andreas Knorr¹ — ¹Technische Universität Berlin, Institut für Theoretische Physik, Nichtlineare Optik und Quantenelektronik, Hardenbergstraße 36, 10623 Berlin, Germany — ²Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany

TMDC heterobilayers are promising candidates for new excitonic phases, since they exhibit long-lived excitonic states with spatially separated electrons and holes located in different atomically thin layers. The relaxation dynamics of these interlayer excitons after their optical excitation is still under investigation.

Based on Heisenberg equations of motion and a correlation expansion of many-body interactions, we discuss the temporally resolved spin dynamics of interlayer excitonic occupations in momentum space: Due to charge separation, interlayer excitons give rise to an out-of-plane self-induced electric field. This leads to Rashba spin-orbit interaction, which is absent in TMDC monolayers. By tuning the total excitonic interlayer occupation, the strength of the internal electric field can be varied and the Rashba spin relaxation can be enhanced or suppressed.

To address the experimental verification of these effects, we discuss, how spin relaxation dynamics of interlayer excitons can be detected in optical pump probe measurements.

Keywords: transition metal dichalcogenides; heterostructure; interlayer exciton; Rashba spin-orbit interaction