G. Kalman et al., DETERMINATION OF THE ENERGY-GAP IN THE ACOUSTIC EXCITATION OF A SUPERLATTICE, Physical review. B, Condensed matter, 50(3), 1994, pp. 2031-2035
Strong interlayer correlations generate a long-wavelength energy gap i
n the acoustic-excitation spectrum of a superlattice, whose magnitude
is determined by the interlayer correlation function. We establish an
iterative scheme for the calculation of the latter, starting from the
well-known correlation function of the isolated two-dimensional electr
on layer. The gap size is displayed as a function of the layer-layer s
eparation and of the coupling parameter within a layer.