2014/08/31 by Zi Yang Meng, Fan Yang, Kuang-Shing Chen +3
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Condensed matter physics #Cooper pair #Fermi surface #Iron-based superconductors research #Ising model #Pairing #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Renormalization group #Square lattice #Superconductivity #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.91.184509
published as Phys. Rev. B 91, 184509 (2015) · 9 pages, 9 figures
arxiv created 2015/05/13 · openalex publication_date 2015/05/13 · arxiv updated 2015/05/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Searching for unconventional Cooper pairing states has been at the heart of superconductivity research since the discovery of BCS superconductors. In particular, spin-triplet odd-parity pairing states were recently revisited due to the possibility of tuning towards topological superconductors. In this context, it is interesting to note a recent proposal that such a spin-triplet pairing instability occurs when the band filling is near van Hove singularities (vHS) associated with momenta away from time-reversal invariant momenta named type-II vHS. However, this result was obtained within a weak coupling renormalization group with Fermi surface patch approximation. To explore superconducting instabilities beyond this weak coupling Fermi surface patch approximation, we perform systematic study on the Hubbard model in a two-dimensional square lattice using three different methods: random phase approximation, large-scale dynamical mean-field theory simulations with continuous time quantum Monte Carlo (CTQMC) impurity solver, and large-scale dynamical cluster simulations with the CTQMC cluster solver. We find, in a wide doping range centered around the type-II van Hove filling, a twofold degenerate, spin-triplet, odd-parity p-wave pairing state emerges due to repulsive interaction, when the Fermi surface is not sufficiently nested. Possible relevance of our findings to the recently discovered superconductors LaO_1\ensuremath-xFxBiS2,\phantom\rule0.16em0exIr_1\ensuremath-xPtxTe2, and proposed doped BC3 are also discussed.