Surface and Bulk Plasmon-polaritons in Periodic Metallic Heterostructures

We have investigated the theory of the plasmon-plariton niodes of a pr iodic metallic heterostructure d i n g use of a local theory. A rich spectrum is found of b t h buU: and surface excitations whose freguency depends upon the dielectric properties of each constituent. We discuss the connections of our analysis with the results obtained within a non-local theory and the effects of retardation. In this paper we report on the results of a theoretical investigation of the collective plamn-polariton spectrum in a periodic metallic heterostructure consisting of an array of alternate metallic slabs characterized by dielectric constants and cg. A schematic il lustration of th i s system is provided in Pig. 1. The unit ce11 of this structure is r-epresented by t w slabs of different material. Such a system can be realized in pmctice by an ar t i f ic ia l ly structured saniconductor. Highly do@ semiconductor heterostructures l ike C,aAs/G+All-&s and InAs/GaSb, or modulation do@ structures 1il;e n-n+-n-n+. . . layers in Si or GaAs, seem a t the m n t to offer the mst flexible and viable solution. An extreme case is representeà by type-I and type-II semiconducting superlattices i n which a pericdic array of quasi two-dimentional electron and/or hole layers is akedded in a dielectric background. l The plasna modes of an infinite pericdic ~ t a l l i c l?eterostructure have been recently studied within a non-local theory based upon a generalized hydrodynanic a p p r ~ a c h . ~ We present here a simpler approach which M e s use of the usual local t h e ~ r ~ . ~ We w i l l assume the electric f ie ld in the A-type region of the nth ce11 of the system to have the forn Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1984542