Robust d-wave superconductivity in the square-lattice $t$-$J$ model

TL;DR

This study uses advanced simulations to map out phases in a doped Mott insulator model, revealing robust d-wave superconductivity driven by charge and spin fluctuations, with implications for understanding high-temperature superconductors.

Contribution

The paper demonstrates the emergence of robust d-wave superconductivity in a square-lattice $t$-$J$ model through large-scale density matrix renormalization group simulations, connecting strongly correlated systems to superconductivity theories.

Findings

Identification of three phases: stripe charge density wave, superconducting without static charge order, and coexisting superconductivity with weak charge order.

Superconducting phase exhibits power-law pairing correlations decaying slower than charge and spin correlations.

Enhanced charge and spin fluctuations at optimal doping induce robust d-wave superconductivity.

Abstract

Unravelling competing orders emergent in doped Mott insulators and their interplay with unconventional superconductivity is one of the major challenges in condensed matter physics. To explore possible superconductivity state in the doped Mott insulator, we study a square-lattice $t$-$J$ model with both the nearest and next-nearest-neighbor electron hoppings and spin Heisenberg interactions. By using the state-of-the-art density matrix renormalization group simulations with imposing charge $U(1)$ and spin $SU(2)$ symmetries on the large-scale six-leg cylinders, we establish a quantum phase diagram including three phases: a stripe charge density wave phase, a superconducting phase without static charge order, and a superconducting phase coexistent with a weak charge stripe order. Crucially, we demonstrate that the superconducting phase has a power-law pairing correlation decaying much slower than the charge density and spin correlations, which is a quasi-1D descendant of the uniform d-wave superconductor in two dimensions. These findings reveal that enhanced charge and spin fluctuations with optimal doping is able to produce robust d-wave superconductivity in doped Mott insulators, providing a foundation for connecting theories of superconductivity to models of strongly correlated systems.