Superconductivity of doped Weyl semimetals: finite-momentum pairing and electronic analogues of the 3He-A phase

Abstract

We study superconducting states of doped inversion-symmetric Weyl semimetals. Specifically, we consider a lattice model realizing a Weyl semimetal with an inversion symmetry and study the superconducting instability in the presence of a short-ranged attractive interaction. With a phonon-mediated attractive interaction, we find two competing states: a fully gapped finite-momentum (FFLO) pairing state and a nodal even-parity pairing state. We show that, in a BCS-type approximation, the finite-momentum pairing state is energetically favored over the usual even-parity paired state and is robust against weak disorder. Though energetically unfavorable, the even-parity pairing state provides an electronic analogue of the 3He-A phase in that the nodes of the even-parity state carry non-trivial winding numbers and therefore support a surface flat band. We briefly discuss other possible superconducting states that may be realized in Weyl semimetals.

9 pages, 2 tables, 2 figures. references are updated and the discussion on the half-qauntum and full-quantum vortices is added

References in corpus (8)

• Superconducting proximity effect and Majorana fermions at the surface of a topological insulator
• Classification of topological insulators and superconductors in three spatial dimensions
• Topological Field Theory of Time-Reversal Invariant Insulators
• Phase transition between the quantum spin Hall and insulator phases in 3D: emergence of a topological gapless phase
• Theory of 2D superconductor with broken inversion symmetry
• Unconventional superconductivity on honeycomb lattice: the theory of Kekule order parameter
• Topological Weyl Semi-metal from a Lattice Model
• Flat band in the core of topological defects: bulk-vortex correspondence in topological superfluids with Fermi points

Cited by in corpus (10)

• Dirac materials
• Chiral anomaly and transport in Weyl metals
• Thermoelectric properties of Weyl and Dirac semimetals
• Topological surface states in nodal superconductors
• Rare region effects dominate weakly disordered 3D Dirac points
• Emergent space-time supersymmetry in 3D Weyl and 2D Dirac semimetals
• Time-reversal invariant topological superconductivity in doped Weyl semimetals
• Crossed surface flat bands of Weyl semimetal superconductors
• Andreev Reflection in Weyl Semimetals
• Topological Pair-Density-Wave Superconducting States