High-pressure phases of crystalline tellurium: A combined Raman and<i>ab initio</i>study

Abstract

A room temperature study of the high-pressure phases of crystalline Te was carried out by combining Raman spectroscopy and density functional theory (DFT)-based calculations. The pressure dependence of the experimental phonon spectrum reveals the occurrence of phase transitions, confirming the high-pressure scenario recently proposed by Hejny and McMahon. The effects of the incommensurate lattice modulation on the vibrational properties of Te are discussed. DFT-based calculations are consistent with the present and previous experimental data and show that the metallization process at 4 GPa is due to charge-bridges between atoms belonging to adjacent chains. A first-principles study of the stability of the 4 GPa phase is here reported and discussed against the insurgence of lattice modulation.