Quantum theory of longitudinal dielectric response properties of a two-dimensional plasma in a magnetic field

Abstract

An analysis of dynamic and nonlocal longitudinal dielectric response properties of a two-dimensional Landau-quantized plasma is carried out, using a thermodynamic Green's function formulation of the RPA with a two-dimensional thermal Green's function for electron propagation in a magnetic field developed in closed form. The longitudinal-electrostatic plasmon dispersion relation is discussed in the low wavenumber regime with nonlocal corrections, and Bernstein mode structure is studied for arbitrary wavenumber. All regimes of magnetic field strength and statistics are investigated. The class of integrals treated here should have broad applicability in other two-dimensional and finite slab plasma studies. The two-dimensional static shielding law in a magnetic field is analyzed for low wavenumber, and for large distances we find V( r) ∼ Q k 0 2r 3 . The inverse screening length k 0 = 2πe 2∂ϱ ∂ξ (ϱ = density, ξ = chemical potential) is evaluated in all regimes of magnetic field strength and all statistical regimes. k 0 exhibits violent DHVA oscillatory behavior in the degenerate zero-temperature case at higher field strengths, and the shielding is complete when ξ = r′ l z.shtsls; ω , but there is no shielding when ξ ≠ r′ l z.shtsls; ω c . A careful analysis confirms that there is no shielding at large distances in the degenerate quantum strong field limit l z.shtsls; ω c > ξ . Since shielding does persist in the nondegenerate quantum strong field limit l z.shtsls; ω c > KT , there should be a pronounced change in physical properties that depend on shielding if the system is driven through a high field statistical transition. (It should be noted that the static shielding law of semiclassical and classical models has no dependence on magnetic field in two dimensions, as in three dimensions.) Finally, we find that the zero field two-dimensional Freidel-Kohn “wiggle” static shielding phenomenon is destroyed by the dispersal of the zero field continuum of electron states into the discrete set of Landau-quantized orbitals due to the imposition of the magnetic field.