  We experimentally demonstrate hot exciton transport in h-BN encapsulated WSe2
monolayers via spatially and temporally resolved photoluminescence measurements
at room temperature. We show that the nonlinear evolution of the mean squared
displacement of the non-resonantly excited hot exciton gas is primarily due to
the relaxation of its excess kinetic energy and is characterized by a
density-dependent fast expansion that converges to a slower, constant rate
expansion. We also observe saturation of the hot exciton gas' expansion rate at
high excitation densities due to the balance between Auger-assisted hot exciton
generation and the phonon-assisted hot exciton relaxation processes.
