Magnetization plateaux and jumps in a class of frustrated ladders: A simple route to a complex behaviour

TL;DR

This paper presents a simple method to predict magnetization plateaux and jumps in frustrated ladder systems by analyzing small spin chains, providing accurate estimates of magnetization behavior across various parameters.

Contribution

It introduces an elementary approach using exact diagonalization and Maxwell constructions to predict complex magnetization features in frustrated ladders.

Findings

Predicted magnetization plateaux and jumps in a broad parameter range.

Provided accurate estimates of magnetization curves using small spin chain models.

Validated predictions with exact and DMRG results.

Abstract

We study the occurrence of plateaux and jumps in the magnetization curves of a class of frustrated ladders for which the Hamiltonian can be written in terms of the total spin of a rung. We argue on the basis of exact diagonalization of finite clusters that the ground state energy as a function of magnetization can be obtained as the minimum - with Maxwell constructions if necessary - of the energies of a small set of spin chains with mixed spins. This allows us to predict with very elementary methods the existence of plateaux and jumps in the magnetization curves in a large parameter range, and to provide very accurate estimates of these magnetization curves from exact or DMRG results for the relevant spin chains.