Juan Cui , Chengliang Xia , Huan Zheng , Miao Zheng , Dafang Li , Yue Chen , Yu Yang
{"title":"Wrinkled layers lead to high in-plane zT values in hexagonal CaAgSb","authors":"Juan Cui , Chengliang Xia , Huan Zheng , Miao Zheng , Dafang Li , Yue Chen , Yu Yang","doi":"10.1016/j.mtphys.2024.101566","DOIUrl":null,"url":null,"abstract":"<div><div>Layered thermoelectric materials (LTMs) have attracted great attention due to their anisotropic transport behaviors that provide an opportunity to disentangle the interrelated electrical and thermal conductivities. In this study, we found that hexagonal CaAgSb (h-CaAgSb) possesses a lower lattice thermal conductivity and a higher electrical conductivity simultaneously along the in-plane direction when compared with the out-of-plane direction. The low in-plane lattice thermal conductivity mainly originates from the low group velocity of longitudinal acoustic phonon modes. Meanwhile, strong anharmonicity is discovered for the low-lying optical phonon modes. On the other hand, the high in-plane electrical conductivity relies on the small effective mass. Thus, both p-type and n-type h-CaAgSb exhibit a high <em>zT</em> over 2.0 along the in-plane direction at the optimal carrier concentrations. The anisotropic transport properties of h-CaAgSb reported in this work may provide guidance to the experiments. More importantly, the physical insights revealed for the disentangled electrical and thermal transport properties may pave the way for finding other excellent LTMs and optimizing the thermoelectric performance through structure engineering.</div></div>","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":null,"pages":null},"PeriodicalIF":10.0000,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Materials Today Physics","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2542529324002426","RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MATERIALS SCIENCE, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
Layered thermoelectric materials (LTMs) have attracted great attention due to their anisotropic transport behaviors that provide an opportunity to disentangle the interrelated electrical and thermal conductivities. In this study, we found that hexagonal CaAgSb (h-CaAgSb) possesses a lower lattice thermal conductivity and a higher electrical conductivity simultaneously along the in-plane direction when compared with the out-of-plane direction. The low in-plane lattice thermal conductivity mainly originates from the low group velocity of longitudinal acoustic phonon modes. Meanwhile, strong anharmonicity is discovered for the low-lying optical phonon modes. On the other hand, the high in-plane electrical conductivity relies on the small effective mass. Thus, both p-type and n-type h-CaAgSb exhibit a high zT over 2.0 along the in-plane direction at the optimal carrier concentrations. The anisotropic transport properties of h-CaAgSb reported in this work may provide guidance to the experiments. More importantly, the physical insights revealed for the disentangled electrical and thermal transport properties may pave the way for finding other excellent LTMs and optimizing the thermoelectric performance through structure engineering.
期刊介绍:
Materials Today Physics is a multi-disciplinary journal focused on the physics of materials, encompassing both the physical properties and materials synthesis. Operating at the interface of physics and materials science, this journal covers one of the largest and most dynamic fields within physical science. The forefront research in materials physics is driving advancements in new materials, uncovering new physics, and fostering novel applications at an unprecedented pace.