Building on the growing evidence based on NMR, magnetization, neutron scattering, ESR, and specific heat that, under pressure, SrCu2(BO3)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.
@article{arxiv.1903.07887,
title = {Competition between intermediate plaquette phases in SrCu$_2$(BO$_3$)$_2$ under pressure},
author = {C. Boos and S. P. G. Crone and I. A. Niesen and P. Corboz and K. P. Schmidt and F. Mila},
journal= {arXiv preprint arXiv:1903.07887},
year = {2019}
}