Negative thermal Hall conductance in a two-dimer Shastry-Sutherland model with a π -flux Dirac triplon

We introduce an effective 2-dimer tight-binding model for the family of Shastry-Sutherland models with geometrically tunable triplon excitations. The Rashba pseudospin-orbit coupling induced by tilted external magnetic field leads to elementary excitations having nontrivial topological properties {\pi}-Berry flux. interplay between in-plane and out-of-plane thus allows us effectively engineer band structure in this bosonic system. In particular, gives rise Berry curvature hotspot near bottom band, at same time significantly increases critical band. calculate explicitly experimental signature thermal Hall effect triplons SrCu2(BO3)2, show a pronounced tunabled transport signals within accessible parameter range, particularly change sign conductance. is also useful reducing bandwidth lowest it can be flexible theoretical platform correlated