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arXiv · 1512.04554

Odd-parity superconductors with two-component order parameters: nematic and chiral, full gap and Majorana node

Jörn W. F. Venderbos·Vladyslav Kozii·Liang Fu
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Abstract

Motivated by the recent experiment indicating that superconductivity in the doped topological insulator Cu$_x$Bi$_2$Se$_3$ has an odd-parity pairing symmetry with rotational symmetry breaking, we study the general class of odd-parity superconductors with two-component order parameters in trigonal and hexagonal crystal systems. In the presence of strong spin-orbit interaction, we find two possible superconducting phases below $T_c$, a time-reversal-breaking (i.e., chiral) phase and an anisotropic (i.e., nematic) phase, and determine their relative energetics from the gap function in momentum space. The nematic superconductor generally has a full quasi-particle gap, whereas the chiral superconductor with a three-dimensional (3D) Fermi surface has point nodes with lifted spin degeneracy, resulting in itinerant Majorana fermions in the bulk and topological Majorana arcs on the surface.

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Jörn W. F. Venderbos, Vladyslav Kozii, Liang Fu. 2015-12-14. Odd-parity superconductors with two-component order parameters: nematic and chiral, full gap and Majorana node. https://doi.org/10.1103/physrevb.94.180504

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