Ground State Phase Diagram of the $t$-$t'$-$J$ model

TL;DR

This study uses large-scale DMRG calculations to map the ground state phase diagram of the $t$-$t'$-$J$ model, revealing distinct behaviors for electron and hole doping and identifying new stripe phases.

Contribution

It provides the first comprehensive phase diagram of the $t$-$t'$-$J$ model on cylinders, highlighting the effects of $t'$ sign on superconductivity and stripe formation.

Findings

Strong $t'>0$ enhances $d$-wave pairing at low doping.

Negative $t'$ suppresses superconductivity and favors stripe phases.

New stripe phase with unpaired holes at specific doping and $t'$ values.

Abstract

We report results of large scale ground state density matrix renormalization group(DMRG) calculations on $t$-$t'$-$J$ cylinders with circumferences 6 and 8. We determine a rough phase diagram which appears to approximate the 2D system. While for many properties, positive and negative $t'$ values ($t'/t = \pm 0.2$) appear to correspond to electron and hole doped cuprate systems, respectively, the behavior of superconductivity itself shows an inconsistency between the model and the materials. The $t'<0$ (hole doped) region shows antiferromagnetism limited to very low doping, stripes more generally, and the familiar Fermi-surface of the hole doped cuprates. However, we find $t'<0$ strongly suppresses superconductivity. The $t'>0$ (electron doped) region shows the expected circular Fermi pocket of holes around the $(\pi,\pi)$ point and a broad low-doped region of coexisting antiferromagnetism and $d$-wave pairing with a strong triplet $p$ component at wave-vector $(\pi,\pi)$ induced by the antiferromagnetism and $d$-wave pairing. The pairing for the electron low-doped system with $t'>0$ is strong and unambiguous in the DMRG simulations. At larger doping another broad region with stripes in addition to weaker $d$-wave pairing and striped $p$-wave pairing appears. In a small doping region near $x=0.08$ for $t'\sim-0.2$, we find a new type of stripe involving unpaired holes located predominantly on chains spaced three lattice spacings apart. The undoped two-leg ladder regions in between mimic the short-ranged spin correlations seen in two-leg Heisenberg ladders.