Transport properties of p-type CaMg_(2)Bi_(2) thermoelectrics  

作　　者：Cheng Sun Xuemin Shi Liangtao Zheng Bo Chen Wen Li 

机构地区：[1]Interdisciplinary Materials Research Center,School of Materials Science and Engineering,Tongji Univ.,4800 Caoan Rd.,Shanghai,201804,China [2]School of Materials Science and Engineering,Tongji Univ.,4800 Caoan Rd.,Shanghai,201804,China [3]Key Laboratory of Performance Evolution and Control for Engineering Structures of Ministry of Education,Tongji Univ.,1239 Siping Rd.,Shanghai,200092,China

出　　处：《Journal of Materiomics》2019年第4期567-573,共7页无机材料学学报（英文）

基　　金：supported by Shanghai Natural Science Foundation(19ZR1459900);the Fundamental Research Funds for the Central Universities.

摘　　要：Due to the complex crystal structure for low lattice thermal conductivity and the tunable valence bands for superior electronic performance,CaAl_(2)Si_(2)-structured AB_(2)C_(2) Zintl compounds have been frequently proven as promising p-type thermoelectric materials.In this work,thermoelectric properties of CaMg_(2)Bi_(2) are systematically investigated in a broad carrier concentration(10^(18)-10^(20) cm^(-3))through Agdoping for comprehensively evaluating its potential for thermoelectric applications.The broad carrier concentration enables a well assessment of the carrier transport properties by single parabolic band with acoustic phonon scattering and a revelation of the carrier transport by multiple valence orbitals when the carrier concentration higher than ~2×10^(19) cm^(-3),leading to a significant enhancement in electronic performance.With the help of additional point defect phonon scattering introduced by BaMg_(2)Bi_(2)-alloying,a reduction in lattice thermal conductivity in the entire temperature range and the lowest one of ~0.7 W/m-K are achieved,leading to a 100% enhancement in average zTave.in addition to the contribution of a multiband transport.This work not only demonstrates CaMg_(2)Bi_(2) as a promising thermoelectric material,but also provides a well understanding of its underlying material physics.

关 键 词：THERMOELECTRIC CaMg_(2)Bi_(2) Carrier concentration Band manipulation 

分 类 号：TG1[金属学及工艺—金属学]