Revealing the Intrinsic Electronic Structure of 3D Half‐Heusler Thermoelectric Materials by Angle‐Resolved Photoemission Spectroscopy

Advanced Science

Martin Dressel¹  Lucky Zaehir Maulana¹  Artem V. Pronin¹  G. Jeffrey Snyder²  Kazuki Imasato²  Fengfeng Zhu³  Xin Li⁴  Jiong Yang⁴  Jianshi Zhou⁵  Xi Chen⁵  Mengyu Yao⁶  Guowei Li⁶  Walter Schnelle⁶  Claudia Felser⁶  Chenguang Fu⁶  Ulrich Burkhardt⁶  Gudrun Auffermann⁶  Tiejun Zhu⁷  Xinbing Zhao⁷  Ming Shi⁸ 

[1] 1. Physikalisches Institut Universität Stuttgart 70569 Stuttgart Germany;Department of Materials Science and Engineering Northwestern University Evanston IL 60208 USA;Jülich Center for Neutron Science JCNS at Heinz Maier‐Leibnitz Zentrum (MLZ) Forschungszentrum Jülich GmbH 85747 Garching Germany;Materials Genome Institute Shanghai University 99 Shangda Road Shanghai 200444 China;Materials Science and Engineering Program Texas Materials Institute The University of Texas at Austin Austin TX 78712 USA;Max Planck Institute for Chemical Physics of Solids Nöthnitzer Str. 40 01187 Dresden Germany;State Key Laboratory of Silicon Materials and School of Materials Science and Engineering Zhejiang University Hangzhou 310027 China;Swiss Light Source Paul Scherrer Institut CH‐5232 Villigen Switzerland;

关键词: bandgap;    electronic structure;    half‐Heusler compounds;    thermoelectric properties;   

DOI  :  10.1002/advs.201902409

来源: DOAJ

【 摘 要 】

Abstract Accurate determination of the intrinsic electronic structure of thermoelectric materials is a prerequisite for utilizing an electronic band engineering strategy to improve their thermoelectric performance. Herein, with high‐resolution angle‐resolved photoemission spectroscopy (ARPES), the intrinsic electronic structure of the 3D half‐Heusler thermoelectric material ZrNiSn is revealed. An unexpectedly large intrinsic bandgap is directly observed by ARPES and is further confirmed by electrical and optical measurements and first‐principles calculations. Moreover, a large anisotropic conduction band with an anisotropic factor of 6 is identified by ARPES and attributed to be one of the most important reasons leading to the high thermoelectric performance of ZrNiSn. These successful findings rely on the grown high‐quality single crystals, which have fewer Ni interstitial defects and negligible in‐gap states on the electronic structure. This work demonstrates a realistic paradigm to investigate the electronic structure of 3D solid materials by using ARPES and provides new insights into the intrinsic electronic structure of the half‐Heusler system benefiting further optimization of thermoelectric performance.

【 授权许可】

Unknown