Pressure effects on the electrical transport and anharmonic lattice dynamics of r-GeTe:A first-principles study  

作　　者：Juan Cui Shasha Li Chengliang Xia Yue Chen Jiaqing He 

机构地区：[1]Shenzhen Key Laboratory of Thermoelectric Materials,Department of Physics,Southern University of Science and Technology,Shenzhen,518055,China [2]Department of Mechanical Engineering,The University of Hong Kong,Pokfulam Road,SAR,Hong Kong,China [3]School of Science,Nanjing University of Posts and Telecommunications,Nanjing,210023,China [4]HKU Zhejiang Institute of Research and Innovation,1623 Dayuan Road,Lin A,311305,China [5]Guangdong Provincial Key Laboratory of Energy Materials for Electric Power,Southern University of Science and Technology,Shenzhen,518055,China

出　　处：《Journal of Materiomics》2021年第6期1190-1197,共8页无机材料学学报（英文）

基　　金：supported by the Research Grants Council of Hong Kong(17201019);the National Natural Science Foundation of China(11934007,11874194and 11874313);the Guangdong Provincial Key Laboratory of Energy Materials for Electric Power(NO.2018B030322001);the Science and Technology Innovation Committee Foundation of Shenzhen(KQTD2016022619565991);the Zhejiang Provincial Natural Science Foundation(LR19A040001);SL acknowledges the support from the startup fund of Nanjing University of Posts and Telecommunications(NY220096).

摘　　要：Various strategies for thermoelectric material optimization have been widely studied and used for promoting electrical transport and suppressing thermal transport.As a nontraditional method,pressure has shown great potential,as it has been applied to obtain a high thermoelectric figure of merit,but the microscopic mechanisms involved have yet to be fully explored.In this study,we focus on r-GeTe,a lowtemperature phase of GeTe,and investigate the pressure effects on the electronic structure,electrical transport properties and anharmonic lattice dynamics based on density functional theory(DFT),the Boltzmann transport equations(BTEs)and perturbation theory.Electronic relaxation times are obtained based on the electron-phonon interaction and the constant relaxation time approximation.The corresponding electrical transport properties are compared with those obtained from previous experiments.Hydrostatic pressure is shown to increase valley degeneracy,decrease the band effective mass and enhance the electrical transport property.At the same time,the increase in the low-frequency phonon lifetime and phonon group velocity leads to an increase in lattice thermal conductivity under pressure.This study provides insight into r-GeTe under hydrostatic pressure and paves the way for a high-pressure strategy to optimize transport properties.

关 键 词：GETE Pressure effect Electronic structure Transport properties 

分 类 号：O17[理学—数学]