Vacancy ordering induced topological electronic transition in bulk Eu2ZnSb2

Honghao Yao; Chen Chen; Wenhua Xue; Fengxian Bai; Feng Cao; Yucheng Lan; Xingjun Liu; Yumei Wang; David J Singh; Xi Lin; Qian Zhang

doi:10.1126/sciadv.abd6162

Vacancy ordering induced topological electronic transition in bulk Eu₂ZnSb₂

Sci Adv. 2021 Feb 5;7(6):eabd6162. doi: 10.1126/sciadv.abd6162. Print 2021 Feb.

Authors

Honghao Yao¹, Chen Chen¹, Wenhua Xue^{1

2}, Fengxian Bai¹, Feng Cao³, Yucheng Lan⁴, Xingjun Liu¹, Yumei Wang², David J Singh⁵, Xi Lin⁶, Qian Zhang⁶

Affiliations

¹ School of Materials Science and Engineering and Institute of Materials Genome and Big Data, Harbin Institute of Technology, Shenzhen 518055, P.R. China.
² Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Science, Beijing 100190, P.R. China.
³ School of Science, Harbin Institute of Technology, Shenzhen 518055, P.R. China.
⁴ Department of Physics and Engineering Physics, Morgan State University, Baltimore, MD 21254, USA.
⁵ Department of Physics and Astronomy and Department of Chemistry, University of Missouri, Columbia, MO 65211, USA. linxi@hit.edu.cn zhangqf@hit.edu.cn singhdj@missouri.edu.
⁶ School of Materials Science and Engineering and Institute of Materials Genome and Big Data, Harbin Institute of Technology, Shenzhen 518055, P.R. China. linxi@hit.edu.cn zhangqf@hit.edu.cn singhdj@missouri.edu.

Abstract

Metal-semiconductor transitions from changes in edge chirality from zigzag to armchair were observed in many nanoribbon materials, especially those based on honeycomb lattices. Here, this is generalized to bulk complex Zintl semiconductors, exemplified by Eu₂ZnSb₂ where the Zn vacancy ordering plays an essential role. Five Eu₂ZnSb₂ structural models are proposed to guide transmission electron microscopy imaging. Zigzag vacancy ordering models show clear metallicity, while the armchair models are semiconducting with indirect bandgaps that monotonously increase with the relative distances between neighboring ZnSb₂ chains. Topological electronic structure changes based on cation ordering in a Zintl compound point toward tunable and possibly switchable topological behavior, since cations in these are often mobile. Thus, their orderings can often be adjusted by temperature, minor alloying, and other approaches. We explain the electronic structure of an interesting thermoelectric and point the way to previously unidentified types of topological electronic transitions in Zintl compounds.

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