From d- to p-wave pairing in the t-t' Hubbard model at zero temperature

TL;DR

This paper introduces a new zero-temperature quantum Monte Carlo algorithm within the dynamical cluster approximation to study pairing symmetries in the 2D Hubbard model, revealing a crossover from d-wave to p-wave pairing.

Contribution

It develops a novel DCA(PQMC) method for zero-temperature analysis and identifies the dominant pairing symmetries and their crossover in the Hubbard model.

Findings

p_{x+y}-wave is dominant in certain parameter regimes

d_{x^2-y^2}-wave is dominant in other regimes

crossover occurs around electron density n~0.4

Abstract

We develop a DCA(PQMC) algorithm which employs the projective quantum Monte Carlo (PQMC) method for solving the equations of the dynamical cluster approximation (DCA) at zero temperature, and apply it for studying pair susceptibilities of the two-dimensional Hubbard-model with next-nearest neighbor hopping. In particular, we identify which pairing symmetry is dominant in the U-n parameter space (U: repulsive Coulomb interaction; n: electron density). We find that p_{x+y}- (d_{x^2-y^2}-) wave is dominant among triplet (singlet) pairings -at least for 0.3<n<0.8 and U<=4t. The crossover between d_{x^2-y^2}-wave and p_{x+y}-wave occurs around n~0.4.