Crystalline and Electronic Structures of the Al_1+xV₂Sn_2–x (x = 0.19) Intermetallic Compound

Abstract

A new ternary phase with a composition Al 1+x V 2 Sn 2-x (x=0.19) has been found during the investigation of the Al-V-Sn ternary system. Single crystal X-ray diffraction measurements reveal that this ternary phase crystallizes with an orthorhombic structure with a = 5.5931(1) Å, b = 18.8017(5) Å and c = 6.7005(2) Å (Space group Cmce). This compound is thus isostructural to the GaV 2 Sn 2 structure type, showing a layered structure composed of vanadium clusters band formed with pentagonal faces intercalated by tin atoms layer. High resolution transmission electron microscopy measurements confirm the orthorhombic structure. Regarding lattice perfection, no dislocation could be identified within the probed Al 1.19 V 2 Sn 1.81 single crystal lamella.Ab initio calculations reveal a reduction of the density of states at the Fermi level, which could be attributed to both a Hume Rothery effect combined with strong spd hybridization.