Doped Antiferromagnets in High Dimension

TL;DR

This paper analyzes the ground-state properties of the t-J model on high-dimensional lattices, revealing phase separation, magnetic order, and stripe phases, with implications for understanding high-temperature superconductors.

Contribution

It extends the analysis of the t-J model to large dimensions, providing a qualitative phase diagram and insights into stripe formation and phase separation.

Findings

Undoped system is an ordered antiferromagnet.

Doped system phase separates into distinct phases.

Stripe phases form with weak Coulomb interactions.

Abstract

The ground-state properties of the t-J model on a d-dimensional hypercubic lattice are examined in the limit of large d. It is found that the undoped system is an ordered antiferromagnet, and that the doped system phase separates into a hole-free antiferromagnetic phase and a hole-rich phase. The latter is electron free if J > 4t and is weakly metallic (and typically superconducting) if J < 4t. The resulting phase diagram is qualitatively similar to the one previously derived for d=2 by a combination of analytic and numerical methods. Domain wall (or stripe) phases form in the presence of weak Coulomb interactions, with periodicity determined by the hole concentration and the relative strength of the exchange and Coulomb interactions. These phases reflect the properties of the hole-rich phase in the absence of Coulomb interactions, and, depending on the value of J/t, may be either insulating or metallic (i.e. an ``electron smectic'').