Topological characterization of classical waves; The Topological origin of magnetostatic surface spin waves

Yamamoto, Kei   ; Thiang, G. C.*; Pirro, P.*; Kim, K.-W.*; Everschor-Sitte, K.*; Saito, Eiji*

Magnetostatic surface spin waves (a.k.a Damon-Eshbach mode) have long been known to have the largest decay lengths of all available modes and are robust against surface shapes and disorders. Combined with their chiral and unidirectional propagation, these features remind one of topologically protected edge states of quantum Hall systems. We present a topological characterization of the dipolar spin wave Hamiltonian, which predicts, via the bulk-edge correspondence, the presence of robust surface spin wave modes without explicitly calculating eigenmodes of a system with boundaries.