Specific heat of disordered Xe films at low temperatures

Abstract

We report measurements of the specific heat $C(0.08 \mathrm{K}<T<7 \mathrm{K})$ of Xe films condensed at low temperatures (\ensuremath{\approx} 6 K). Low-$T$ x-ray diffraction indicates that the films are crystalline but strongly disordered, with very small crystallites. The specific heat is very large compared to bulk Xe, and the excess specific heat can be attributed to surface modes and to tunneling states.