Neutron diffraction study of the crystal structure of TlInSe₂ at high pressure

Abstract

We have investigated the crystal structure of strongly anisotropic semiconductor TlInSe 2 by neutron diffraction method under high pressure upto P = 3.3 GPa. It was shown that the tetragonal phase of TlInSe 2 crystal (the space group I4/mcm) is stable in the whole investigated range of pressure. The lattice parameters dependence of the pressure and the unit cell volume are obtained, the linear coefficients of compressibility and the bulk moduli are calculated. At the low pressure, obtained value of compressibility for the lattice parameter a is k[Formula: see text] = 14.23 × 10[Formula: see text] GPa[Formula: see text] and for c is k[Formula: see text] = 5.93 × 10[Formula: see text] GPa[Formula: see text]. Obtained values for bulk modulus B 0 and its pressure derivative B[Formula: see text] in tetragonal phase are 30(7) GPa and 4(1), respectively.