Magnetic exchange induced Weyl state in a semimetal EuCd2Sb2

Hao Su; Benchao Gong; Wujun Shi; Haifeng Yang; Hongyuan Wang; Wei Xia; Zhenhai Yu; Peng-Jie Guo; Jinhua Wang; Linchao Ding; Liangcai Xu; Xiaokang Li; Xia Wang; Zhiqiang Zou; Na Yu; Zengwei Zhu; Yulin Chen; Zhongkai Liu; Kai Liu; Gang Li; Yanfeng Guo

arXiv · 1903.12532

Magnetic exchange induced Weyl state in a semimetal EuCd2Sb2

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Abstract

Magnetic Weyl semimetals (WSMs) bearing long-time pursuing are still very rare. We herein identified magnetic exchange induced Weyl state in EuCd2Sb2, a semimetal in type IV magnetic space group, via performing high magnetic field (B) magneto-transport measurements and ab initio calculations. For the A-type antiferromagnetic (AFM) structure of EuCd2Sb2, external B larger than 3.2 T can align Eu spins to be fully polarized along the c-axis and consequently drive the system into a ferromagnetic (FM) state. Measurements up to B ~ 55 T revealed a striking Shubnikov-de Hass oscillation imposed by a nontrivial Berry phase. We unveiled a phase transition from a small-gap AFM topological insulator into a FM WSM in which Weyl points emerged along the {\Gamma}-Z path. Fermi arcs on (100) and (010) surfaces are also revealed. The results pave a way towards realization of various topological states in a single material through magnetic exchange manipulation.

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Hao Su, Benchao Gong, Wujun Shi, Haifeng Yang, Hongyuan Wang, Wei Xia, Zhenhai Yu, Peng-Jie Guo, Jinhua Wang, Linchao Ding, Liangcai Xu, Xiaokang Li, Xia Wang, Zhiqiang Zou, Na Yu, Zengwei Zhu, Yulin Chen, Zhongkai Liu, Kai Liu, Gang Li, Yanfeng Guo. 2019-03-29. Magnetic exchange induced Weyl state in a semimetal EuCd2Sb2. https://arxiv.org/abs/1903.12532

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