Competition between d-wave superconductivity and antiferromagnetism in the 2D Hubbard model

TL;DR

This paper investigates the zero-temperature competition between antiferromagnetism and d-wave superconductivity in the 2D Hubbard model, revealing how their interplay depends on interaction strength and doping, with phase transitions and coexistence regimes.

Contribution

It provides a detailed analysis of the phase competition in the 2D Hubbard model using Cellular Dynamical Mean Field Theory, highlighting the dependence on coupling strength and doping.

Findings

At strong coupling, a first-order transition occurs between pure phases.

At weak coupling, coexistence of phases is observed.

Phase separation accompanies first-order transitions.

Abstract

We study the competition of antiferromagnetism and d-wave superconductivity at zero-temperature in the two-dimensional Hubbard model using Cellular Dynamical Mean Field Theory. The interplay between the two phases depends strongly on the strength of the correlation. At strong coupling ($ U \ge 8t$) the two phases do not mix, and a first-order transition takes place as a function of doping between two pure phases. At weak-coupling ($U \le 8t$) the two order parameters coexist within the same solution in a range of doping and the system smoothly evolves from the antiferromagnet to the superconductor. When the transition between the superconducting and the antiferromagetic phases is of the first-order, it is accompanied by a phase separation.