Gruneisen parameter and thermal expansion coefficients of NiSi2 from first-principles

Abstract

Metal silicides are highly important materials due to their fascinating properties and diverse applications in microelectronics. In this work, we have studied the Gruneisen parameter, thermal expansion and other thermodynamic properties of nickel-disilicide (NiSi2) using the density-functional theoretical framework. The Gruneisen parameter dispersions, thermal expansion coefficients, heat capacities and bulk modulus are calculated from volume dependence of phonon frequencies. The frequencies of zone-centre phonon modes are calculated to be 311 cm−1 (infrared active) and 323 cm−1 (Raman active) and are in good agreement with reported Raman scattering data. The thermodynamic Gruneisen parameter and Debye temperature are calculated to be 1.85 K and 535 K respectively. The calculated linear thermal expansion coefficient (∼12.1 × 10−6 K−1) is found to be in good agreement with its recently reported experimental value. The theoretical results are interesting and are expected to stimulate experimental investigations of thermal properties of NiSi2 and other silicides.