Confined collective excitations of self-standing and supported planar periodic particle arrays

Confined collective excitations of self-standing and supported planar periodic particle arrays.

We find the conditions for the existence of trapped modes in planar periodic particle arrays. Confined excitations of TE and TM symmetry are observed in symmetric environments, originating in lattice resonances that are signalled by the onset of new diffraction beams. This mechanism of mode formation is shown to be inhibited by the presence of a dielectric interface in an asymmetric configurati...

Excitation of confined modes on particle arrays.

We describe both theoretically and experimentally the existence and excitation of confined modes in planar arrays of gold nanodisks. Ordered 2D lattices of monodispersive nanoparticles are manufactured, embedded in a silica matrix, and exposed to evanescent prism-coupling illumination, leading to dark features in the reflectivity, which signal the presence of confined modes guided along the arr...

Self–consistent Dual Boson approach to single-particle and collective excitations in correlated systems

Single Particle and Collective Spin Excitations in Semimagnetic Quantum Wells

Collective and single-particle spin-flip excitations of a two-dimensional electron gas in a semimagnetic Cd1−xMnxTe quantum well are observed by resonant Raman scattering. Application of a magnetic field splits the spin-subbands and a spin-polarization is induced in the electron gas. Above some critical field, a collective spin-flip mode, which disperses with in-plane wave vector, dominates the...

Single Particle versus Collective Electronic Excitations 1 Philip

As a rst approximation, a metal can be modelled as an electron gas. A non-interacting electron gas has a continuous spectrum of electron-hole pair excitations. At each wavevector ~ Q with j~ Qj less than the maximum Fermi surface spanning vector (2kF ) there is a continuous set of electron-hole pair states, with a maximum energy but no gap (the minimum energy is zero.) Once the Coulomb interact...