p-wave Superfluidity by Spin-Nematic Fermi Surface Deformation

Abstract

We study attractively interacting fermions on a square lattice with dispersion relations exhibiting strong spin-dependent anisotropy. The resulting Fermi surface mismatch suppresses the s-wave BCS-type instability, clearing the way for unconventional types of order. Unbiased sampling of the Feynman diagrammatic series using Diagrammatic Monte Carlo methods reveals a rich phase diagram in the regime of intermediate coupling strength. Instead of a proposed Cooper-pair Bose metal phase [A. E. Feiguin and M. P. A. Fisher, Phys. Rev. Lett. 103, 025303 (2009)] we find an incommensurate density wave at strong anisotropy and two different p-wave superfluid states with unconventional symmetry at intermediate anisotropy.

published version, supplemental material included as appendix, 4+4 pages, 5+7 figures

References in corpus (6)

• The ALPS project release 1.3: open source software for strongly correlated systems
• Fermi liquid instabilities in the spin channel
• Bold Diagrammatic Monte Carlo: When Sign Problem is Welcome
• Unconventional metamagnetic electron states in orbital band systems
• Exotic paired states with anisotropic spin-dependent Fermi surfaces
• Exotic paired phases in ladders with spin-dependent hopping