Plasma Waves in Anisotropic Superconducting Films Below and Above the Plasma Frequency

الأصل · EN

We consider wave propagation inside an anisotropic superconducting film sandwiched between two semi-infinite non-conducting bounding dieletric media such that along the c-axis, perpendicular to the surfaces, there is a plasma frequency ωₚ below the superconducting gap. Propagation is assumed to be parallel to the surfaces in the dielectric medium, where amplitudes decay exponentially.Below ωₚ, the amplitude also evanesces inside the film, and we retrieve the experimentally measured lower dispersion relation branch, ω∝ √β, and the recently proposed higher frequency branch, ω∝ 1/√β.Above ωₚ, propagation is of the guided wave type, i.e., a dispersive plane wave confined inside the film that reflects into the dielectric interfaces,and the modes are approximately described by ω≈ ωₚ √ 1+ (β/β₀)², where β₀ is discussed here.