A class of Heisenberg models with the orthogonal dimer ground states

TL;DR

This paper introduces a class of three-dimensional Heisenberg models with exact orthogonal dimer ground states, providing insights into the magnetic properties of layered spin gap systems like SrCu_2(BO_3)_2.

Contribution

It constructs a 3D Heisenberg model with an exact dimer ground state, extending the known 2D models and explaining the magnetic behavior of certain layered materials.

Findings

Exact dimer ground state in 3D model

Relevance to SrCu_2(BO_3)_2 magnetic properties

Layered exchange interactions explained

Abstract

Extensions of the Shastry-Sutherland model are possible in various ways. In particular, it is possible to construct a natural model in three dimensions which has the exact dimer ground state. Recently found spin gap system SrCu_2(BO_3)_2 has this structure. The exchange constants between the layers is expected to be smaller than the intra-layer couplings. However, the exactness of the dimer state for the three dimensional structure is important to understand why magnetic properties of SrCu_2(BO_3)_2 are described well by the two dimensional model.