Effect of magnetic field on collective modes of two-dimensional electron liquids: A molecular dynamics study

Abstract

We have produced molecular dynamics simulations of a classical two-dimensional electron liquid subject to a constant magnetic field perpendicular to its plane for various values of the coupling parameter and the magnetic field strength. The results were used to obtain the corresponding density and transverse current correlation functions and to study their collective mode structure, in particular, the dispersion curves of the longitudinal plasmon modes and the transverse shear modes. Our dispersion results have been compared with theoretical predictions of the quasilocalized charge approximation (QLCA) and its extensions, for zero and nonzero magnetic fields. We conclude that the QLCA theory explains quite well the plasmon dispersion for all values of the coupling parameter and magnetic field that we investigated; however, the theory is not as good in explaining the shear mode dispersion. We have also observed an additional frequency peak for a range of coupling parameters in both correlation functions, but only for nonzero magnetic fields.