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arXiv · 1807.06247

Exotic Node Line in ternary MgSrSi-type crystals

Jinling Lian·Lixian Yu·Qi-Feng Liang·Jian Zhou·Rui Yu·Hongming Weng
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Abstract

Node line (NL) band-touchings protected by mirror symmetry (named as $m$-NL), the product of inversion and time reversal symmetry $\mathcal{S=PT}$ ($s$-NL), or nonsymmorphic symmetry are nontrivial topological objects of topological semimetals (SMs) in the Brillouin Zone (BZ). In this work, we screened the family of MgSrSi-type crystals using first principles calculations, and discovered that more than 70 members are NLSMs. A new type of multi-loop structure was found in AsRhTi that a $s$-NL touches robustly with a $m$-NL at some "nexus point", and in the meanwhile a second $m$-NL crosses with the $s$-NL to form a Hopf-link. Unlike the previously proposed Hopf-link formed by two $s$-NLs or two $m$-NLs, a Hopf-link formed by a $s$-NL and a $m$-NL requires a minimal three-band model to characterize its essential electronic structure. The associated topological surface states on different surfaces of AsRhTi crystal were also obtained. Even more complicated and exotic multi-loop structure of NLs were predicted in AsFeNa and PNiNb. Our work may shed light on search for exotic multi-loop NLSMs in real materials.

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Jinling Lian, Lixian Yu, Qi-Feng Liang, Jian Zhou, Rui Yu, Hongming Weng. 2018-07-17. Exotic Node Line in ternary MgSrSi-type crystals. https://arxiv.org/abs/1807.06247

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