  For monolayer transition metal chalcogenides (TMDs), electrons and excitons
in different valleys can be driven to opposite directions by the Berry
curvature, serving as a valley-dependent effective magnetic field. In addition
to monolayer TMDs, Van der Waals heterostructures provide an attractive
platform for emerging valley physics and devices with superior physics
properties. Interlayer excitons in TMD heterostructures have a long valley
lifetime as compared to monolayer intralayer excitons. Here we report an
interlayer exciton valley polarization and valley Hall effect in MoS2/WSe2 in
room temperature. The separation for excitons with different valley index is
observed with polarization-dependent photoluminescence mapping. The exciton
separation is perpendicular to their transport directions. The valley Hall
effect for indirect excitons is sustained even at room temperature, in contrast
with the cryo-temperatures in previous experiments in monolayer TMDs. Room
temperature demonstration of the indirect exciton valley polarization and
valley Hall effect might open new perspectives for the development of
opto-valleytronic devices based on TMD heterostructures.
