Edge spin-density modes in quantum dots in a magnetic field

Abstract

We investigate electronic excitations in GaAs–AlGaAs quantum dots by means of resonant inelastic light scattering in the presence of an external magnetic field Image . At magnetic field Image , we observe a series of discrete electronic excitations, namely, charge-density excitations (CDEImage ) and spin-density excitations (SDEImage ), in one and the same quantum dot sample. We find at finite magnetic field, additionally to the well-known splitting of the CDEImage modes (plasmons), a quite similar splitting of the lowest SDE mode whose energy is very close to the single-particle level spacing in the quantum dot. In analogy to the edge magnetoplasmon, we call this excitation an edge spin-density mode.