Stripes in the two-dimensional t-J model with infinite projected entangled-pair states

TL;DR

This paper uses infinite projected entangled-pair states to simulate the 2D t-J model, revealing stripe patterns with lower energy than uniform phases and identifying optimal hole densities for energy and superconductivity.

Contribution

It introduces a generalized iPEPS method for the 2D t-J model and demonstrates the stability of stripe phases with specific hole densities.

Findings

Stripe phases have lower energy than uniform phases.

Optimal hole density for energy minimization is around 0.5 per unit length.

Superconducting order peaks at hole densities around 0.75-0.8.

Abstract

We simulate the $t$ $J$ model in two dimensions by means of infinite projected entangled-pair states (iPEPS) generalized to arbitrary unit cells, finding results similar to those previously obtained by the density-matrix renormalization group (DMRG) for wide ladders. In particular, we show that states exhibiting stripes, {\it i.e}. a unidirectional modulation of hole-density and antiferromagnetic order with a $\pi$-phase shift between adjacent stripes, have a lower variational energy than uniform phases predicted by variational and fixed-node Monte Carlo simulations. For a fixed unit-cell size the energy per hole is minimized for a hole density $\rho_l\sim 0.5$ per unit length of a stripe. The superconducting order parameter is maximal around $\rho_l\sim 0.75-0.8$.