Light absorption properties related to long-living ensemble of spin excitations in an unpolarized quantum Hall system
S. Dickmann
Institute for Solid State Physics of RAS, 142432 Chernogolovka, Russia
Abstract
In connection with recent studies of extremely long-living spin-cyclotron
excitations (actually
magneto-excitons) in a quantum Hall electron gas, we discuss contribution to the
light-absorption
related to the presence of a magneto-exciton ensemble in this purely electronic
system. Since the weakly interacting
excitations have to obey the Bose-Einstein statistics, one can expect appearance
of a coherent state in the ensemble. A
comparative analysis of both incoherent and coherent cases is done. Conditions
for a phase transition from the
incoherent state to the coherent one are discussed.