EXCHANGE EFFECT IN COUPLED 2-DIMENSIONAL ELECTRON-GAS SYSTEMS

The distribution of electrons in two parallel two-dimensional electron sheets in close proximity at low temperatures is investigated. We find that due to the exchange interaction a symmetric structure may have a ground state in which all electrons are transferred to one of the sheets. This occurs if the separation between the two systems is sufficiently small and the two-dimensional electron gas density is sufficiently low. The exchange interaction consequently leads to a bistability with respect to electron population in the two-sheet system which may be useful for future electronic devices, such as memory elements.