Spin-charge separation in two-leg t-J ladders

TL;DR

This study uses DMRG to explore spin-charge separation in two-leg t-J ladders, showing it can emerge under certain conditions and may persist in wider systems.

Contribution

It provides new evidence that spin-charge separation can occur in two-leg ladders, extending understanding beyond one-dimensional systems.

Findings

Spin-charge separation signatures appear in certain parameter regimes.

Transition from Luther Emery to Luttinger liquid phase observed.

Results suggest spin-charge separation may persist in wider ladder systems.

Abstract

Spin-charge separation is a hallmark of one-dimensional fermionic systems, yet its realization in higher dimensions remains an open question. To address this issue, we investigate a two-leg t-J ladder using the density matrix renormalization group (DMRG) method and its time-dependent extension. By analyzing ground-state correlations and single-particle removal spectra, we systematically examine the effects of plaquette diagonal hopping, spin exchange, and hole doping. Within appropriate parameter regimes, these factors drive the system from the well-known Luther Emery phase, with gapped spin and gapless charge modes, into a Luttinger liquid phase characterized by gapless spin and charge excitations, where signatures of spin-charge separation emerge. In combination with previous studies using exact diagonalization, our results provide evidence that spin-charge separation may persist in wider ladder systems.