High-pressure X-ray diffraction and Mössbauer spectroscopy study of Fe1.087Te

The compression mechanism of Fe1.087Te was studied by high-pressure X-ray diffraction at ambient temperature. Fe1.087Te retains tetragonal symmetry up to the highest measured pressure of 25.67 GPa and the structural parameters obtained by high-pressure X-ray diffraction were used as input parameters for electronic structure calculation at the DFT level. The electronic structure calculations show that the chemical bonding between Te atoms across the van der Waals gap is enhanced at elevated pressures and the Fermi surface undergoes at topological change at ≈4 GPa reflecting a change from 2- to 3-dimensional character of the electronic structure. Mössbauer spectra of Fe1.087Te recorded at elevated pressures and ambient temperature showed no indication of a pressure-induced change of the spin-state and the obtained isomer shifts and quadrupole splittings are consistent with Fe2+ ion with S = 1. •The pressure-induced enhancement the Te-Te bonding across the van der Waals gap in Fe1.087Te elucidated by DFT calculations in combination with Crystal Orbital Hamilton Population Analysis.•The pressure-induced topological change of the Fermi surface at ≈4 GPa reflecting a change from 2- to 3-dimensional character of the electronic structure.•The fact that our high-pressure Mössbauer data rules out possible pressure-induced spinstate changes of the Fe2+ ions in Fe1.087Te.