Anomalous Exciton Hall effect

Speaker: Valerii Kozin (University of Basel, Klinovaja group)

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Title: Anomalous Exciton Hall effect

Speaker: GHE Fellow Valerii Kozin (University of Basel, Klinovaja group)

Date: June 29th 2022 @ 11am

Place: Albert-Ludwigs-University Freiburg

Abstract:

It is well known that electrically neutral excitons can still be affected by crossed electric and
magnetic fields that make them move in a direction perpendicular to both fields. We show that a
similar effect appears in the absence of external electric fields, in the case of scattering of an exciton
flow by charged impurities in the presence of the external magnetic field. As a result, the exciton
flow changes the direction of its propagation that may be described in terms of the Hall conductivity
for excitons. We develop a theory of this effect, which we refer to as the anomalous exciton Hall
effect, to distinguish it from the exciton Hall effect that arises due to the valley selective exciton
transport in transition metal dichalcogenides. According to our estimations, the effect is relatively
weak for optically active or bright excitons in conventional GaAs quantum wells, but it becomes
significant for optically inactive or dark excitons, because of the difference of the lifetimes. This
makes the proposed effect a convenient tool for spatial separation of dark and bright excitons.