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arXiv · 1705.01424

Hourglass Dirac Chain Metal in Rhenium Dioxide

Shan-Shan Wang·Ying Liu·Zhi-Ming Yu·Xian-Lei Sheng·Shengyuan A. Yang
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Abstract

Nonsymmorphic symmetries, which involve fractional lattice translations in crystalline materials, can generate exotic types of fermionic excitations that are robust against spin-orbit coupling. Here we report on a hourglass-type dispersion in the bulk of three-dimensional rhenium dioxide crystals, as dictated by its nonsymmorphic symmetries. Due to time reversal and inversion symmetries, each band has an additional two-fold degeneracy, making the neck crossing-point of the hourglass four-fold degenerate. Remarkably, close to the Fermi level, the neck crossing-point traces out a Dirac chain--a chain of connected four-fold-degenerate Dirac loops--in the momentum space. The symmetry protection, the transformation under symmetry-breaking, and the associated topological surface states of the hourglass Dirac chain are discussed.

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Shan-Shan Wang, Ying Liu, Zhi-Ming Yu, Xian-Lei Sheng, Shengyuan A. Yang. 2017-05-03. Hourglass Dirac Chain Metal in Rhenium Dioxide. https://doi.org/10.1038/s41467-017-01986-3

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