  The exponentially strong damping of the conventional Friedel oscillations at
elevated temperature T as well as due to disorder poses a severe problem to the
Hume-Rothery (HR) stabilization mechanism of amorphous and quasicrystalline
alloys. We show that quantum correlations induced by electron-electron
interactions in the presence of random impurity scattering can play an
important role in stabilizing these systems: When there is strong
backscattering off local ion clusters, the static electron density response
chi(0,q) acquires a powerlaw divergence at q=2k_F even at T>0. This Fermi
surface singularity leads to an enhancement as well as to a systematical phase
shift of the Friedel oscillations, consistent with experiments. In addition,
the spatial decay exponent is reduced, strongly supporting the validity of a
HR-like mechanism at T>0. This effect may be accounted for in pseudopotential
calculations through the local field factor.
