Random-phase-approximation treatment of edge magnetoplasmons: Edge-state screening and nonlocality

A microscopic treatment of edge magnetoplasmons within a random-phase approximation framework is presented for strong magnetic fields, low temperatures, and integer filling factors {ν}. It is valid for negligible dissipation and lateral confining potentials smooth on the scale of the magnetic length l₀ but sufficiently steep that the Landau-level (LL) flattening can be neglected. LL coupling, screening by edge states, and nonlocal contributions to the current density are taken into account. In addition to the fundamental mode with typical dispersion relation ω~qₓln(qₓ), fundamental modes with acoustic dispersion relation ω~qₓ are obtained for ν>2. For ν=1,2 a dipole mode exists, with dispersion relation ω~qₓ³, that is directly related to nonlocal responses.