Thermodynamic Properties of the Heisenberg Antiferromagnet on a Railroad-Trestle Lattice with Asymmetric Leg Interactions

TL;DR

This study investigates the temperature-dependent specific heat of the antiferromagnetic Heisenberg model on an asymmetric railroad-trestle lattice, revealing distinct multi-peak structures depending on lattice parameters.

Contribution

It introduces an approximation method for eigenvalue distribution functions to analyze thermodynamic properties of a generalized lattice model.

Findings

Majumdar-Ghosh model exhibits a two-peak specific heat structure.

Systems near the sawtooth-lattice point show a three-peak structure.

Finite size data up to 28 spins used for thermodynamic limit extrapolation.

Abstract

Using an approximation method for eigenvalue distribution functions, we study the temperature dependence of specific heat of the antiferromagnetic Heisenberg model on the asymmetric railroad-trestle lattice. This model contains both the sawtooth-lattice and Majumdar-Ghosh models as special cases. Making extrapolations to the thermodynamic limit using finite size data up to 28 spins, it is found that specific heat of the Majumdar-Ghosh model has a two-peak structure in its temperature dependence and those of systems near the sawtooth-lattice point have a three-peak structure.