Effective Theory of Magnetization Plateaux in the Shastry-Sutherland Lattice

TL;DR

This paper derives an effective model for magnetization plateaux in the Shastry-Sutherland lattice using the CORE method, explaining observed and predicted plateaux at various fractions of saturation.

Contribution

It introduces a non-perturbative effective model for triplet excitations, clarifying previous theoretical inconsistencies and predicting new stable magnetization plateaux.

Findings

Observation of magnetization plateaux at 1/8, 1/4, 1/3, 1/9, 1/6, and 2/9.

Resolution of discrepancies among earlier theoretical models.

Application of CORE method to derive the effective model.

Abstract

We use the non-perturbative Contractor-Renormalization method (CORE) in order to derive an effective model for triplet excitations on the Shastry-Sutherland lattice. For strong enough magnetic fields, various magnetization plateaux are observed, e.g. at 1/8, 1/4, 1/3 of the saturation, as found experimentally in a related compound. Moreover, other stable plateaux are found at 1/9, 1/6 or 2/9. We give a critical review of previous works and try to resolve some apparent inconsistencies between various theoretical approaches.