First-principles study of structural and electronic properties of multiferroic oxide Mn3TeO6 under high pressure

TL;DR

This study uses first-principles calculations to analyze the structural, magnetic, and electronic changes of Mn3TeO6 under high pressure, revealing a phase transition and insights into band gap variations.

Contribution

It provides a detailed first-principles investigation of pressure-induced phase transition and electronic properties of Mn3TeO6, clarifying previous experimental discrepancies.

Findings

R-3 phase transforms to P21/n at 7.58 GPa with volume collapse

Calculated band gaps align with experiments for R-3 phase, overestimate for P21/n

Transition slightly reduces the band gap of Mn3TeO6

Abstract

Mn3TeO6 (MTO) has been experimentally found to adopt a P21/n structure under high pressure, which exhibits a significantly smaller band gap compared to the atmospheric R-3 phase. In this study, we systematically investigate the magnetism, structural phase transition and electronic properties of MTO under high pressure through first-principles calculations. Both R-3 and P21/n phases of MTO are antiferromagnetic at zero temperature. The R-3 phase transforms to the P21/n phase at 7.58 GPa, accompanied by a considerable volume collapse of about 6.47%. Employing the accurate method that combines DFT+U and G0W0, the calculated band gap of R-3 phase at zero pressure is very close to the experimental values, while that of the P21/n phase is significantly overestimated. The main reason for this difference is that the experimental study incorrectly used the Kubelka-Munk plot for the indirect band gap to obtain the band gap of the P21/n phase instead of the Kubelka-Munk plot for the direct band gap. Furthermore, our study reveals that the transition from the R-3 phase to the P21/n phase is accompanied by a slight reduction in the band gap.