Excess low-temperature specific heat in K0.3MoO3.

Abstract

The thermal conductivity and specific heat of the charge-density-wave compound ${\mathrm{K}}_{0.3}$Mo${\mathrm{O}}_{3}$ have been measured between 0.1 and 1 K. The thermal conductivity is typical of a good crystal, while the specific-heat measurements show an excess contribution which is linear in temperature and corresponds to approximately 2\ifmmode\times\else\texttimes\fi{}${10}^{20}$ states/eV ${\mathrm{cm}}^{3}$. This excess specific heat indicates significant randomness, in spite of good stoichiometry and crystal quality. We speculate that the phase distortions of the randomly pinned charge-density wave are responsible for the excess low-lying excitations.