Specific Heat Capacity of Amorphous Materials near the Absolute Zero.
Robert Karsdorf 1,Ferdinand Werr1, Armin Lenhart 1, Dominique de Ligny 2, Pascal Richet 3
1 Fakultät Werkstofftechnik, Technische Hochschule Nürnberg, 90489 Nürnberg
2 Institute of Glass and Ceramics, University of Erlangen-Nuremberg, 91058 Erlangen
3 Institut de Physique du Globe de Paris, Université Paris, 75005 Paris
A special feature of amorphous solids is taking place close to the absolute zero in the range between 5 and 25 Kelvin. The temperature dependency of specific heat capacity for
crystalline bodies is usually well described by the Debye’s model that predicts that the ratio Cp / T3
should remain constant. This law was verified by many measurements. For glasses
near the absolute zero, a significant deviation is observed. Indeed for glasses with different composition, an excess of heat capacity has been detected in the measurements. If the data
are plotted in a Cp / T3
diagram, excess values looking like a broad peak are noticed. This paper examines at extent a link between the glass composition, the height of the peak and the
temperature of the peak maximum. For binary alkali silicate glasses significant correlations between the measurements and the concentration and the nature of the alkali metal ions were
found. It is also confronted to data obtained by vibrational spectroscopy where the so called Boson peak was measured.