Phase transitions of electron-hole and unbalanced electron systems in coupled quantum wells in high magnetic fields

The superfluidity of spatially separated electrons and holes and of an unbalanced two-layer electron system in a high magnetic field is considered. The temperature $T_c$ of the Kosterlitz-Thouless transition to a superfluid state is obtained as a function of magnetic field H and interlayer separation D. The equation of state for the magnetoexciton system in the quasiclassical regime is analyzed. The transition from excitonic phase to electron-hole phase is considered. Possible experimental manifestations of the predicted effects are briefly discussed.