Low-Energy Properties of Antiferromagnetic Spin-1/2 Heisenberg Ladders with an Odd Number of Legs

TL;DR

This paper investigates the low-energy properties of antiferromagnetic spin-1/2 Heisenberg ladders with an odd number of legs, revealing their similarity to longer-range spin chains and analyzing how key parameters change with system size.

Contribution

It introduces an effective low-energy description for odd-leg ladders and applies advanced computational methods to analyze their magnetic properties.

Findings

Low-temperature scaling similar to longer-range spin chains

Spinon velocity remains constant with more legs

Energy scale parameter decreases significantly with system size

Abstract

An effective low-energy description for multi-leg spin-1/2 Heisenberg ladders with an odd number of legs is proposed. Using a newly developed Monte Carlo loop algorithm and exact diagonalization techniques, the uniform and staggered magnetic susceptibility and the entropy are calculated for ladders with 1, 3, and 5 legs. These systems show a low-temperature scaling behavior similar to spin-1/2 chains with longer ranged unfrustrated exchange interactions. The spinon velocity does not change as the number of legs increases, but the energy scale parameter decreases markedly.