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arXiv · 1704.01661

Double helix nodal line superconductor

Xiao-Qi Sun·Biao Lian·Shou-Cheng Zhang
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Abstract

Time-reversal invariant superconductors in three dimensions may contain nodal lines in the Brillouin zone, which behave exactly as Wilson loops of 3d momentum-space Chern-Simons theory of the Berry connection. Here we study the conditions of realizing linked nodal lines (Wilson loops), which yield a topological contribution to the thermal magnetoelectric coefficient that is given by the Chern-Simons action. We find the essential conditions are the existence of torus or higher genus fermi surfaces and spiral spin textures. We construct such a model with two torus fermi surfaces, where a generic spin-dependent interaction leads to double-helix-like linked nodal lines as the superconductivity is developed.

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Xiao-Qi Sun, Biao Lian, Shou-Cheng Zhang. 2017-10-03. Double helix nodal line superconductor. https://doi.org/10.1103/physrevlett.119.147001

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