Tensor network study of the Shastry-Sutherland model in zero magnetic field

TL;DR

This study uses tensor network methods to map the phase diagram of the two-dimensional Shastry-Sutherland model, revealing an intermediate plaquette phase and precise phase transition points.

Contribution

It provides the first systematic tensor network analysis confirming the intermediate plaquette phase and accurately determining phase boundaries in the model.

Findings

Confirmation of the intermediate plaquette phase.

Precise determination of phase transition points.

Absence of a stable columnar-dimer phase.

Abstract

We simulate the Shastry-Sutherland model in two dimensions by means of infinite projected entangled-pair states (iPEPS) - a variational tensor network method where the accuracy can be systematically controlled by the so-called bond dimension. Besides the well established dimer and N\'eel phase iPEPS confirms the presence of an intermediate phase with plaquette long-range order, and we determine its phase boundaries with high accuracy. The first order phase transition for $J=0.675(2)$ between dimer and plaquette phase is compatible with previous series expansion results. iPEPS predicts a weak first-order phase transition between plaquette and N\'eel phase occurring for $J=0.765(15)$. We do not find a stable intermediate columnar-dimer phase, even when we bias the state towards this order.