Valence-bond theory of highly disordered quantum antiferromagnets

TL;DR

This paper introduces a large-N variational method based on valence-bond theory to accurately model the magnetism in highly disordered quantum antiferromagnets, aligning with experimental observations.

Contribution

It develops a disorder-generalized valence-bond approach that matches predictions of the strong-disorder renormalization group and provides an analytic solution without adjustable parameters.

Findings

Method captures qualitative and quantitative predictions across temperature range

Mapping to a hard-sphere fluid yields an exact analytic solution

Results agree with experimental data on disordered quantum antiferromagnets

Abstract

We present a large-N variational approach to describe the magnetism of insulating doped semiconductors based on a disorder-generalization of the resonating-valence-bond theory for quantum antiferromagnets. This method captures all the qualitative and even quantitative predictions of the strong-disorder renormalization group approach over the entire experimentally relevant temperature range. Finally, by mapping the problem on a hard-sphere fluid, we could provide an essentially exact analytic solution without any adjustable parameters.