Antiferromagnetism and superconductivity in a model with extended pairing interactions

Abstract

The competition between antiferromagnetism and the d + id superconducting state is studied in a model with near and next near neighbour interactions in the absence of any on-site repulsion. A mean field study shows that it is possible to have simultaneous occurrence of an antiferromagnetic and a singlet d + id superconducting state in this model. In addition, such a coexistence generates a triplet d + id superconducting order parameter with centre of mass momentum Q = (π, π) dynamically having the same orbital symmetry as the singlet superconductor. Inclusion of next nearest neighbour hopping in the band stabilises the d xy superconducting state away from half filling, the topology of the phase diagram, though, remains similar to the near neighbour model. In view of the very recent observation of a broad region of coexistence of antiferrmagnetic and unconventional superconducting states in organic superconductors, the possibility of observation of the triplet state has been outlined.

Coexistence of spin density wave, d-wave singlet and staggered π-triplet superconductivity

“…In the present paper we study the coexistence of singlet dwave SC with SDWs and in particular we focus on the induced staggered triplet SC component and new behavior that may result because of the presence of these three order parameters. Several studies of the competition of unconventional SC with SDWs and the possibility of an emergent staggered π-triplet pairing are available [8][9][10][11][12][13]. For example, in [10,12] scattering by non-magnetic impurities is shown to stabilize a phase with all three order parameters (OPs) whereas in [11,13] the induced π-pairing is studied in the context of deviations from half-filling.…”

“…Several studies of the competition of unconventional SC with SDWs and the possibility of an emergent staggered π-triplet pairing are available [8][9][10][11][12][13]. For example, in [10,12] scattering by non-magnetic impurities is shown to stabilize a phase with all three order parameters (OPs) whereas in [11,13] the induced π-pairing is studied in the context of deviations from half-filling.…”

Exotic magnetic states in Pauli-limited superconductors

“…A study of the Hubbard model showed that for dwave superconductivity, coexistent SDW order and triplet superconductivity arise generally at half filling [29]. It was also shown that in a twodimensional spin lattice with com peting nearest and nextnearest neighbor interactions, dwave superconductivity can coexist with modulated triplet super conductivity [30]. Zhang derived a SO(5) symmetry principle that unifies antiferromagnetism and dwave superconductiv ity, and furthermore explains their coexistence [31].…”