Exact Demonstration of Magnetization Pleateaus and First Order Dimer-N\'eel Phase Transitions in a Modified Shastry-Sutherland Model for SrCu$_2$(BO$_3$)$_2$

TL;DR

This paper rigorously demonstrates first-order phase transitions and magnetization plateaus in a modified Shastry-Sutherland model relevant to SrCu$_2$(BO$_3$)$_2$, revealing detailed phase diagram features.

Contribution

It provides an exact proof of phase transitions and magnetization plateaus in a generalized model for SrCu$_2$(BO$_3$)$_2$, advancing understanding of its magnetic properties.

Findings

First-order Dimerized-Néel phase transition established

Magnetization plateaus at specific magnetization values identified

Phase diagram includes gap-closing continuous transitions

Abstract

We study a generalized Shastry-Sutherland model for the material SrCu$_2$(BO$_3$)$_2$. Along a line in the parameter space, we can show rigorously that the model has a first order phase transition between Dimerized and N\'eel-ordered ground states. Furthermore, when a magnetic field is applied in the Dimerized phase, magnetization plateaus develop at commensurate values of the magnetization. We also discuss various aspects of the phase diagram and properties of this model away from this exactly soluble line, which include gap-closing continuous transitions between Dimerized and magnetically ordered phases.