Low temperature heat capacity of Ti3SiC2

Calorimetric measurements between 2 and 10 K have been made on Ti3SiC2. The molar heat capacity, c, data can be fitted to the sum of an electronic and a lattice contribution: c=γT+βT3. The β value of 0.049 mJ/mol K4 yields a Debye temperature of 620 K, typical of high stiffness and hardness ceramic materials such as TiC. This value is significantly higher than the Debye temperature measured from elastic measurements. The γ value of 5.21 mJ/mol K2 is a measure of the density of states at the Fermi level. This value, when normalized to a per Ti atom basis, is higher than that of TiC0.97, but roughly half that of Ti metal, implying that covalent-type bonding induced electron localization increases in going from Ti to Ti3SiC2 to TiC. It also partially explains the excellent electrical and thermal conductivities of Ti3SiC2.