Band degeneracy enhanced thermoelectric performance in layered oxyselenides by first-principles calculations  

作　　者：Ning Wang Menglu Li Haiyan Xiao Zhibin Gao Zijiang Liu Xiaotao Zu Sean Li Liang Qiao 

机构地区：[1]School of Physics,University of Electronic Science and Technology of China,Chengdu,China [2]Department of Physics,National University of Singapore,Singapore,Republic of Singapore [3]Department of Physics,Physics,Lanzhou City University,Lanzhou,China [4]School of Materials,University of New South Wales,Sydney,Australia

出　　处：《npj Computational Materials》2021年第1期158-170,共13页计算材料学（英文）

基　　金：Haiyan Xiao was supported by the NSAF Joint Foundation of China(Grant No.U1930120);Liang Qiao was supported by National Natural Science Foundation of China(Grant No.11774044,52072059);Zhibin Gao acknowledges the financial support from MOE tier 1 funding of NUS Faculty of Science,Singapore(Grant No.R-144-000-402-114);The theoretical calculations are performed using the supercomputer resources at TianHe-1 located at National Supercomputer Center in Tianjin.

摘　　要：Band degeneracy is effective in optimizing the power factors of thermoelectric(TE)materials by enhancing the Seebeck coefficients.In this study,we demonstrate this effect in model systems of layered oxyselenide family by the density functional theory(DFT)combined with semi-classical Boltzmann transport theory.TE transport performance of layered LaCuOSe and BiCuOSe are fully compared.The results show that due to the larger electrical conductivities caused by longer electron relaxation times,the n-type systems show better TE performance than p-type systems for both LaCuOSe and BiCuOSe.Besides,the conduction band degeneracy of LaCuOSe leads to a larger Seebeck coefficient and a higher optimal carrier concentration than n-type BiCuOSe,and thus a higher power factor.The optimal figure of merit(ZT)value of 1.46 for n-type LaCuOSe is 22%larger than that of 1.2 for n-type BiCuOSe.This study highlights the potential of wide band gap material LaCuOSe for highly efficient TE applications,and demonstrates that inducing band degeneracy by cations substitution is an effective way to enhance the TE performance of layered oxyselenides.

关 键 词：DEGENERACY SELENIDE LAYERED 

分 类 号：TB34[一般工业技术—材料科学与工程]