Competing Nodal d-Wave Superconductivity and Antiferromagnetism

Competing unconventional superconductivity and antiferromagnetism widely exist in several strongly correlated quantum materials whose direct simulation generally suffers from fermion sign problem. Here, we report unbiased quantum Monte Carlo (QMC) simulations on a sign-problem-free repulsive toy model with same on site symmetries as the standard Hubbard model on a 2D square lattice. Using QMC simulations, supplemented with mean-field and continuum field-theory arguments, we find that it hosts three distinct phases: a nodal d-wave phase, an antiferromagnet, and an intervening phase which hosts coexisting antiferromagnetism and nodeless d-wave superconductivity. The transition from the coexisting phase to the antiferromagnet is described by the 2 + 1-D XY universality class, while the one from the coexisting phase to the nodal d-wave phase is described by the Heisenberg-Gross-Neveu theory. The topology of our phase diagram resembles that of layered organic materials which host pressure tuned Mott transition from antiferromagnet to unconventional superconductor at half-filling.

Automated summary

Research has found that an unbiased quantum Monte Carlo simulation of a repulsive toy model with the same on-site symmetries as the standard Hubbard model can exhibit three distinct phases: a nodal d-wave phase, an antiferromagnet, and an intervening phase with coexisting antiferromagnetism and nodeless d-wave superconductivity. The transitions between these phases are described by different theoretical models, showing similar topology to layered organic materials undergoing pressure-tuned Mott transition.