High pressure phases of crystalline tellurium

TL;DR

This paper investigates high-pressure phases of crystalline tellurium using Raman spectroscopy and DFT calculations, identifying phase transitions at 4 GPa and 8 GPa and exploring metallization and lattice modulation effects.

Contribution

It provides combined experimental and theoretical insights into tellurium's phase transitions and metallization under high pressure, including the role of lattice modulation.

Findings

Phase transitions at 4 GPa and 8 GPa confirmed.

Metallization at 4 GPa due to charge-bridge formation.

Agreement between DFT calculations and experimental data.

Abstract

A study of high pressure solid Te was carried out at room temperature using Raman spectroscopy and Density Functional Theory (DFT) calculations. The analysis of the P-dependence of the experi- mental phonon spectrum reveals the occurrence of phase transitions at 4 GPa and 8 GPa confirming the high-pressure scenario recently proposed. The effects of the incommensurate lattice modulation on the vibrational properties of Te is discussed. DFT calculations agree with present and previous experimental data and show the metallization process at 4 GPa being due to the development of charge-bridges between atoms belonging to adjacent chains. A first-principles study of the stability of the 4 GPa phase is reported and discussed also in the light of the insurgence of lattice modulation.