Strongly Interacting Two-Dimensional Dirac Fermions

TL;DR

This paper demonstrates how ultracold atoms in a 2D optical lattice can realize strongly interacting Dirac fermions, revealing unconventional superconductivity with a dome-shaped phase diagram similar to high-temperature superconductors.

Contribution

It introduces a realistic experimental setup for strongly interacting 2D Dirac fermions with gauge fields, showing emergent unconventional superconductivity and complex phase behavior.

Findings

Unconventional superconductivity with non-local bond pairing observed.

Dome-shaped superconducting phase diagram similar to high-Tc materials.

Realistic experimental conditions for observing these phenomena.

Abstract

We show how strongly interacting two-dimensional Dirac fermions can be realized with ultracold atoms in a two-dimensional optical square lattice with an experimentally realistic, inherent gauge field, which breaks time-reversal and inversion symmetries. We find remarkable phenomena in a temperature range around a tenth of the Fermi-temperature, accessible with present experimental techniques: at zero chemical potential, besides a conventional s-wave superconducting phase, unconventional superconductivity with non-local bond pairing arises. In a temperature versus doping phase diagram, the unconventional superconducting phase exhibits a dome structure, reminiscent of the phase diagram for high-temperature superconductors and heavy fermions.