The layered metal Ti2PTe2

Crystals of Ti2PTe2 have been synthesised by chemical vapour transport. Ti2PTe2 crystallises, isostructural to the mineral tetradymite (Bi2STe2), in the space group R (3) over barm With Unit-cell parameters a = 16387(2)angstrom and c = 28.486(2)angstrom for the hexagonal setting. in the structure, layers of isolated phosphide and telluride anions form an ordered close sphere-packing with titanium cations filling two-thirds of the octahedral voids From XANES fluorescence the presence of Ti4+ is clearly established. In accordance with the ionic formula (Ti4+)(2) (P3-)(Te2-)(2)(e(-)) metallic conductivity (rho = 40 mu Omega cm at 300 K) and nearly temperature-independent paramagnetism are found. The electronic band structure shows bands of titanium states crossing the Fermi level in directions corresponding to the ab-plane and a band gap along the c-axis. (C) 2008 Elsevier Inc. All rights reserved.