d-wave superconducting phase diagram of the two dimensional Hubbard model

Karan Aryanpour, Thereza Paiva, Warren E. Pickett +1 more

Adolfo Avella, Ferdinando Mancini, Francesco Paolo Mancini +1 more

ARMEN N. KOCHARIAN, Chia‐Wei Yang, Y. L. Chiang

Arooj Aslam, Yuan-Yuan Xiang, Cheng-Wei Li +2 more

Abstract Using the singular-mode functional renormalization group method, we studied the doping-dependent phase diagram of the two-dimensional extended Hubbard model on square lattice. At half-filling, a variety of states strongly compete, including spin-density wave, charge-density wave, phase separation, as well as d -wave and s -wave superconductivity (SC). Upon electron doping, the system exhibits a strong preference for superconducting states. At slight dopings, the spin-density wave phase is strongly suppressed, and d -wave SC region expands into positive U , V region. At moderate dopings, a region of degenerated p -wave superconductivities emerge for positive U and negative V . Our results demonstrate how doping tunes the dominant fluctuations, suppressing density waves and stabilizing unconventional superconducting states in two dimensions.

Xin-Zhong Yan

Junya Otsuki, Hartmut Hafermann, Alexander I. Lichtenstein

The dual-fermion approach offers a way to perform diagrammatic expansion around the dynamical mean field theory. Using this formalism, the influence of antiferromagnetic fluctuations on the self-energy is taken into account through ladder-type diagrams in the particle-hole channel. The resulting phase diagram for the (quasi-)two-dimensional Hubbard model exhibits antiferromagnetism and $d$-wave superconductivity. Furthermore, a uniform charge instability, i.e., phase separation, is obtained in the low-doping regime around the Mott insulator. We also examine spin/charge density wave fluctuations including $d$-wave symmetry. The model exhibits a tendency towards an unconventional charge density wave, but no divergence of the susceptibility is found.