Hourglass Dirac chain metal in rhenium dioxide.

ABSTRACT: Nonsymmorphic symmetries, which involve fractional lattice translations, can generate exotic types of fermionic excitations in crystalline materials. Here we propose a topological phase arising from nonsymmorphic symmetries-the hourglass Dirac chain metal, and predict its realization in the rhenium dioxide. We show that ReO2 features hourglass-type dispersion in the bulk electronic structure dictated by its nonsymmorphic space group. 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 tra

SUBMITTER: Wang SS 

PROVIDER: S-EPMC5705673 | biostudies-literature | 2017 Nov

REPOSITORIES: biostudies-literature