Plasmonics in group III nitrides

Synopsis

An experimental study of near–field light-matter interaction by tip-enhanced Raman scattering (TERS) with polarized light in doped group-III nitride heterostructures will be presented. The experimental data are explained with a quantum mechanical interpretation, which takes into account the role of plasmon polaritons and the evanescent field. The selection rules in TERS are caused by photon tunnelling through the perturbation of the evanescent field, with the consequent polariton annihilation. In second part, we show that a degenerate, three-dimensional electron gas stabilizes a novel class of quasiparticles, named collexons, by many-particle effects dominated by exchange of electrons with the Fermi gas. The observation of collexons and their stabilization with rising doping concentration is enabled by a superior crystal quality due to a close to ideal substitution of the host atom with the dopant.