Electronic structure and thermoelectric transport properties of the golden Th2S3-type Ti2O3 under pressure

Bin Xu,Jing Zhang,Yusheng Wang,Changzheng Gao,Yuanxu Wang

doi:10.1063/1.4953063

Abstract

A lot of physical properties of Th2S3-type Ti2O3 have investigated experimentally, hence, we calculated electronic structure and thermoelectric transport properties by the first-principles calculation under pressure. The increase of the band gaps is very fast from 30GP to 35GP, which is mainly because of the rapid change of the lattice constants. The total density of states becomes smaller with increasing pressure, which shows that Seebeck coefficient gradually decreases. Two main peaks of Seebeck coefficients always decrease and shift to the high doping area with increasing temperature under pressure. The electrical conductivities always decrease with increasing temperature under pressure. The electrical conductivity can be improved by increasing pressure. Electronic thermal conductivity increases with increasing pressure. It is noted that the thermoelectric properties is reduced with increasing temperature.

Highlights

The electronic structure of bulk titanium sesquioxide (Ti2O3) has been the object of much experimental and theoretical investigation in the past few decades
The total density of states becomes smaller with increasing pressure, which shows that Seebeck coefficient gradually decreases
We find that the calculated lattice constants are a=7.8764 Å, b=2.8517 Å, c=8.1957 Å, which are very close to those found experimentally.[11,12]

Summary

Introduction

The electronic structure of bulk titanium sesquioxide (Ti2O3) has been the object of much experimental and theoretical investigation in the past few decades. Titanium oxides are well studied because they share the same transition metal but with different structures and properties.[1,2,3,4,5,6,7,8] An oxide with trivalent titanium, i.e. Ti2O3, has a dual importance. This is a system with an intermediate between TiO and TiO2 ratio of O/Ti = 1.5, and intermediate titanium valence; for this reason an investigation of its properties is critically important for an understanding of the Ti–O system. Sesquioxides are an important class of materials for condensed matter physics, since their fundamental properties partly predetermine those of the more complex ‘mixed sesquioxides’ with exciting physical behaviour

Methods

Results

Conclusion