Synthesis, physical properties and band structure of non-magnetic Y3AlC

Abstract Y 3 AlC has been synthesized by arc melting and subsequent annealing. Rietveld analysis of the powder x-ray diffraction (XRD) data confirms cubic Pm -3 m structure. Electrical resistivity ( ρ ) of Y 3 AlC exhibits metallic behaviour. No sign of superconductivity is observed down to the lowest measurement temperatures of 4.2 K in ρ , and 2 K in magnetic susceptibility ( χ ) and specific heat ( C p ) measurements. The value of the electronic specific heat coefficient γ is 1.36 mJ/K 2  mol from which the density of states (DOS) at the Fermi energy ( E F ) is obtained as 0.57 states/eV.unit cell. The value of Debye temperature θ D is estimated to be 315 K. Electronic band structure calculations of Y 3 AlC reveal a pseudo-gap in the DOS at E F leading to a small value of 0.5 states/eV unit cell which matches quite well with that obtained from γ . Non-zero value of the DOS indicates metallic behaviour as confirmed by our ρ data. Covalent and ionic bonding seem to co-exist with metallic bonding in Y 3 AlC as indicated by van Arkel- Ketelaar triangle for Zintl-like systems.