Anomalous Lattice Properties of Manganese Monosilicide: the Thermodynamic Approach

Abstract

The temperature dependences of the thermal and elastic MnSi properties are analyzed within the limits of the self-consistent approach. The role of the anharmonicity of acoustic and optical lattice vibrations is analyzed. It is demonstrated that anomalously weak anharmonicity is characteristic for acoustic phonons. In particular, this explains the temperature dependence of the MnSi bulk compressive modulus. The one-electron contribution is estimated and the anomalous non-lattice contribution to the formation of the temperature dependences of heat capacity and volume thermal expansion coefficients.