Larkin-Ovchinnikov state of superconducting Weyl metals: Fundamental differences between pairings restricted and extended in the $\text{k}$-space

Abstract

Two common approaches of studying theoretically the property of a superconductor are shown to have significant differences, when they are applied to the Larkin-Ovchinnikov state of Weyl metals. In the first approach the pairing term is restricted by a cutoff energy to the neighborhood of the Fermi surface, whereas in the second approach the pairing term is extended to the whole Brillouin zone. We explore their difference by considering two minimal models for the Weyl metal. For a model giving a single pair of Weyl pockets, both two approaches give a partly-gapped (fully-gapped) bulk spectrum for small (large) pairing amplitude. However, for very small cutoff energy, a portion of the Fermi surface can be completely unaffected by the pairing term in the first approach. For the other model giving two pairs of Weyl pockets, while the bulk spectrum for the first approach can be fully gapped, the one from the second approach has a robust line node, and the surface states are also changed qualitatively by the pairing. We elucidate the above differences by topological arguments and analytical analyses. A factor common to both of the two models is the tilting of the Weyl cones which leads to asymmetric normal state band structure with respect to the Weyl nodes. For the Weyl metal with two pairs of Weyl pockets, the band folding leads to a double degeneracy in the effective model, which distinguishes the pairing of the second approach from all others.

27 pages, 11 figures

References in corpus (17)

• Phase transition between the quantum spin Hall and insulator phases in 3D: emergence of a topological gapless phase
• Classification of stable three-dimensional Dirac semimetals with nontrivial topology
• Strong Correlations and Magnetic Frustration in the High Tc Iron Pnictides
• Topology of crystalline insulators and superconductors
• Pairing Symmetry in a Two-Orbital Exchange Coupling Model of Oxypnictides
• Classification of reflection symmetry protected topological semimetals and nodal superconductors
• Superconductivity of doped Weyl semimetals: finite-momentum pairing and electronic analogues of the 3He-A phase
• Evidence of Andreev bound states as a hallmark of the FFLO phase in $\kappa$-(BEDT-TTF)${}_2$Cu(NCS)${}_2$
• Time-reversal invariant topological superconductivity in doped Weyl semimetals
• Unconventional superconductivity on honeycomb lattice: the theory of Kekule order parameter
• Unconventional superfluid in a two-dimensional Fermi gas with anisotropic spin-orbit coupling and Zeeman fields
• Crossed surface flat bands of Weyl semimetal superconductors
• Topologically stable gapless phases in nonsymmorphic superconductors
• Gapless topological Fulde-Ferrell superfluidity induced by in-plane Zeeman field
• Moving and merging of Dirac points on a square lattice and hidden symmetry protection
• Topological Phase Transitions and a Two-Dimensional Weyl Superconductor in a Half-Metal/Superconductor Heterostructure
• Searching for two-dimensional Weyl superconductors in heterostructures

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