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arXiv · 2412.03972

Type-II Dirac nodal chain semimetal CrB4

Xiao-Yao Hou·Ze-Feng Gao·Peng-Jie Guo·Jian-Feng Zhang·Zhong-Yi Lu
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Abstract

Dirac nodal line semimetals with topologically protected drumhead surface states have attracted intense theoretical and experimental attention over a decade. However, the study of type-II Dirac nodal line semimetals is rare, especially the type-II nodal chain semimetals have not been confirmed by experiment due to the lack of ideal material platform. In this study, based on symmetry analysis and the first-principles electronic structure calculations, we predict that CrB4 is an ideal type-II Dirac nodal chain semimetal protected by the mirror symmetry. Moreover, there are two nodal rings protected by both space-inversion and time-reversal symmetries in CrB4. More importantly,in CrB4 the topologically protected drumhead surface states span the entire Brillouin zone at the Fermi level. On the other hand, the electron-hole compensation and the high mobility of Dirac fermions can result in large magnetoresistance effects in CrB4 according to the two-band model.Considering the fact that CrB4 has been synthesized experimentally and the spin-orbit coupling is very weak, CrB4 provides an ideal material platform for studying the exotic properties of type-II Dirac nodal chain semimetals in experiment.

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Xiao-Yao Hou, Ze-Feng Gao, Peng-Jie Guo, Jian-Feng Zhang, Zhong-Yi Lu. 2024-12-05. Type-II Dirac nodal chain semimetal CrB4. https://arxiv.org/abs/2412.03972

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