Similarities in the Cp/T3 peaks in amorphous and crystalline metals

A low-temperature peak in Cp/T3 vs T is ubiquitous to glasses. It arises from an abundance of low-frequency vibrations, the origin of which remains unclear. A comparable Cp/T3 vs T peak is observed in crystals due to the dispersion of acoustic phonons and/or the excitation of optical phonons. We compared the Cp/T3 vs T peaks in metallic and oxide glasses to elemental crystals by analyzing specific heat, phonon density of states, and elastic constant data. We observe no clear distinction in the peak temperature or amplitude between metallic glasses and crystals. Surprisingly, the peak is larger in single crystal Pd40Cu40P20 than in glassy Pd40Cu40P20.