# Competition between intermediate plaquette phases in SrCu$_2$(BO$_3$)$_2$ under pressure

## TL;DR

This paper investigates the competition between different intermediate phases in SrCu$_2$(BO$_3$)$_2$ under pressure, showing that a full plaquette phase better matches experimental data than an empty plaquette phase.

## Contribution

It demonstrates that a minimal model with varying intra- and inter-dimer couplings favors a full plaquette phase over the empty plaquette phase, aligning better with experiments.

## Key findings

- Full plaquette phase replaces empty plaquette phase under certain couplings.
- Full plaquette phase aligns more closely with experimental observations.
- The model explains the intermediate phase observed under pressure.

## Abstract

Building on the growing evidence based on NMR, magnetization, neutron scattering, ESR, and specific heat that, under pressure, SrCu$_2$(BO$_3$)$_2$ has an intermediate phase between the dimer and the N\'eel phase, we study the competition between two candidate phases in the context of a minimal model that includes two types of intra- and inter-dimer interactions without enlarging the unit cell. We show that the empty plaquette phase of the Shastry-Sutherland model is quickly replaced by a quasi-1D full plaquette phase when intra- and/or inter-dimer couplings take different values, and that this full plaquette phase is in much better agreement with available experimental data than the empty plaquette one.