Doped Heisenberg chains: spin-S generalizations of the supersymmetric t-J model

TL;DR

This paper introduces a family of exactly solvable doped Heisenberg chains with arbitrary spin S, generalizing the supersymmetric t-J model, and analyzes their low-temperature spin-charge separation and thermodynamic properties.

Contribution

It constructs and solves a new class of integrable models for spin-S doped Heisenberg chains using algebraic Bethe Ansatz, extending the supersymmetric t-J model.

Findings

Models exhibit spin-charge separation at low temperatures.

Charge sector described by a free bosonic theory.

Magnetic excitations follow an SU(2)-invariant theory.

Abstract

A family of exactly solvable models describing a spin-S Heisenberg chain doped with mobile spin-(S-1/2) carriers is constructed from gl(2|1)-invariant solutions of the Yang-Baxter equation. The models are generalizations of the supersymmetric t-J model which is obtained for S=1/2. We solve the model by means of the algebraic Bethe Ansatz and present results for the zero temperature and thermodynamic properties. At low temperatures the models show spin charge separation, i.e. contain contributions of a free bosonic theory in the charge sector and an SU(2)-invariant theory describing the magnetic excitations. For small carrier concentration the latter can be decomposed further into an SU(2) level-2S Wess-Zumino-Novikov-Witten model and the minimal unitary model M_p with p=2S+1.