Emergence of Topologically Stable Dirac Dispersions in a Fermionic Shastry–Sutherland Model

Abstract

Electronic structure of fermionic Shastry-Sutherland model, which is recently revealed to have a rich phase diagram, is investigated further in detail. We find that if the spin–orbit coupling exists, the quantum spin Hall insulator phase is also possible, in addition to the phases discovered in the previous study. Furthermore, first-principles calculation is performed for an existing material SrCu2(BO3)2 that has Shastry-Sutherland type lattice network, and the obtained results confirm those established with the tight-binding model.