High Temperature Superconductivity in a Lightly Doped Quantum Spin Liquid

TL;DR

This study uses density-matrix renormalization group methods to demonstrate that lightly doped quantum spin liquids on a square lattice exhibit power-law superconducting correlations, indicating potential high-temperature superconductivity.

Contribution

It reveals the emergence of power-law superconducting correlations in a frustrated quantum spin liquid model with light doping, a novel finding in the context of high-temperature superconductivity research.

Findings

Power-law superconducting correlations with K_sc ≈ 1 observed.

Superconducting susceptibility diverges as T approaches 0.

Spin correlations remain exponentially decaying, indicating smooth evolution from the parent state.

Abstract

We have performed density-matrix renormalization group studies of a square lattice $t$-$J$ model with small hole doping, $\delta\ll 1$, on long 4 and 6 leg cylinders. We include frustration in the form of a second-neighbor exchange coupling, $J_2 = J_1/2$, such that the undoped ($\delta=0$) "parent" state is a quantum spin liquid. In contrast to the relatively short range superconducting (SC) correlations that have been observed in recent studies of the 6-leg cylinder in the absence of frustration, we find power law SC correlations with a Luttinger exponent, $K_{sc} \approx 1$, consistent with a strongly diverging SC susceptibility, $\chi \sim T^{-(2-K_{sc})}$ as the temperature $T\to 0$. The spin-spin correlations - as in the undoped state - fall exponentially suggesting that the SC "pairing" correlations evolve smoothly from the insulating parent state.