High-pressure effect on the chain-like crystal structure of the semiconductors TlFeSe2 and TlFeS2

Abstract

The crystal structure of the semiconductors TlFeSe 2 and TlFeS 2 has been studied by mean of neutron diffraction at room temperature and high pressure up to 4.2 GPa and 5.2 GPa, respectively. The chain-like monoclinic crystal structure with space group C2/m remains unchanged in both compounds in the entire pressure range. The anisotropic lattice compression and the large difference in the bulk modulus and the compressibility coefficients of the structural parameters of the two compounds have been observed. The mechanism of the observed phenomena was discussed. The enhancement of the one-dimensional antiferromagnetic and metallic character was predicted.