Spin-dependent dipole excitation in alkali-metal nanoparticles

Abstract

We study the spin-dependent electronic excitations in alkali-metal nanoparticles. Using numerical and analytical approaches, we focus on the resonances in the response to spin-dependent dipole fields. In the spin-dipole absorption spectrum for closed-shell systems, we investigate in detail the lowest-energy excitation, the "surface paramagnon" predicted by L. Serra et al. [Phys. Rev. A 47, R1601 (1993)]. We estimate its frequency from simple assumptions for the dynamical magnetization density. In addition, we numerically determine the dynamical magnetization density for all low-energy spin-dipole modes in the spectrum. Those many-body excitations can be traced back to particle-hole excitations of the noninteracting system. Thus, we argue that the spin-dipole modes are not of collective nature. In open-shell systems, the spin-dipole response to an electrical dipole field is found to increase proportionally with the ground-state spin polarization.

12 pages, 9 figures

References in corpus (4)

• Surface plasmon in metallic nanoparticles: renormalization effects due to electron-hole excitations
• Spin and density longitudinal response of quantum dots in time-dependent local-spin-density approximation
• A semiclassical approach to the ground state and density oscillations of quantum dots
• Scissors modes in triaxial metal clusters

Cited by in corpus (4)

• Lifetime of the surface magnetoplasmons in metallic nanoparticles
• Plasmonic modes in cylindrical nanoparticles and dimers
• Ultrafast dynamics of a spin-polarized electron plasma with magnetic ions
• Phase-space modelling of solid-state plasmas