Charge density glass dynamics – Soft potentials and soft modes

An universal fingerprint of glasses has been found in low-temperature thermodynamic properties of charge/spin density wave (C/SDW) systems. Deviations from the well-known Debye, elastic continuum prediction for specific heat (flat Cp/T3 plot) appear as two anomalies; the upturn below 1K and a broad bump at T∼10K (named Boson peak in glasses). The first one, inherent of localized two level systems within the shalow corrugated phase space, exhibits slow relaxation with the complex dynamics. The second one, “Boson peak-like peak” was attributed to the pinned mode and incomplete softening of CDW superstructural mode. We discuss similar Cp(T) features found also in incommensurate dielectrics with well documented soft-mode anomalies.