S. Pan et Th. Lin, EXTENSION THEORY FOR MAGNETIC EXCITATIONS OF ORDERED FERROMAGNETIC SYSTEMS, Communications in Theoretical Physics, 20(1), 1993, pp. 1-10
The extension theory for lattice Green functions is used to study the
magnetic excitations of some ordered ferromagnetic systems. The local
density of magnon states for the bulk as well as for the surface, edge
and corner is presented.