SUPERFLUIDITY OF EXCITONS IN A HIGH MAGNETIC-FIELD

In a high magnetic field, such that the distance between the Landau levels exceeds the exciton Rydberg, the triplet interaction term becomes the lowest state of the system. Under these circumstances, a weak pair interaction in the triplet ground state opens a new opportunity to forming the Bose-Einstein condensate and a superfluid state of excitons at a relatively high temperature. The existence of the Bose condensate due to an essential decrease of the interaction between excitons and an increase of their binding energy in a high magnetic field are established. We show that the excitation spectrum satisfies the Landau criterion for superfluidity, and discuss the observable effects of the Bose condensate of excitons.