Theory of short-range magnetic order for the t-J model

TL;DR

This paper develops a self-consistent, spin-rotation-invariant theory for magnetic short-range order in the 2D t-J model, revealing a dominance of paramagnetic phases with strong short-range correlations over long-range magnetic order.

Contribution

It introduces a novel self-consistent approach using a slave-boson representation to analyze short-range magnetic order in the t-J model, bridging itinerant and localized magnetic behaviors.

Findings

Suppression of long-range antiferromagnetic order in favor of short-range correlations.

Effective doping-dependent exchange interaction derived from the model.

Paramagnetic phase with strong short-range magnetic correlations.

Abstract

We present a self-consistent theory of magnetic short-range order based on a spin-rotation-invariant slave-boson representation of the 2D t-J model. In the functional-integral scheme, at the nearest-neighbour pair-approximation level, the bosonized t-J Lagrangian is transformed to a classical Heisenberg model with an effective (doping-dependent) exchange interaction which takes into account the interrelation of ``itinerant'' and ``localized'' magnetic behaviour. Evaluating the theory in the saddle-point approximation, we find a suppression of antiferromagnetic and incommensurate spiral long-range-ordered phases in the favour of a paramagnetic phase with pronounced antiferromagnetic short-range correlations.