ON THE SUPERFLUIDITY AND CRYSTALLIZATION IN A SYSTEM OF SURFACE ELECTRONS PAIRED WITH SUBSTRATE HOLES

The collective properties of system of surface electrons on a film of superfluid He-4 paired with substrate holes is discussed. The case whe n size of pairs is much smaller than their average separation is consi dered. The possibility of superfluidity of pairs is investigated, and the estimation of superfluid transition temperature is given. The cond itions of competition between the superfluid transition and the pair c rystallization with formation of a dipole crystal is discussed. The me lting temperature of the dipole crystal is calculated in the assumptio n that the crystallization occurs according to the Kosterlitz-Thouless mechanism. The conditions under which the quantum effects prevent the crystallization down to zero temperature are determined. The problem of localization of pairs by impurities or structure irregularities is analyzed.