The g-factors of discrete levels in nanoparticles

Abstract

Spin-orbit scattering suppresses Zeeman splitting of individual energy levels in small metal particles. This suppression becomes significant when the spin-orbit scattering rate τ_{so}^{-1} is comparable with the quantum level spacing δ. The g-factor exhibits mesoscopic fluctuations; at small δτ_{so} it is distributed according to the Maxwell distribution. At δτ_{so}\to 0 the average g-factor levels off at a small value g\sim(l/L)^{1/2} given by the ratio of the electron mean free path l to the particle size L. On the contrary, in 2D quantum dots the g-factor is strongly enhanced by spin-orbit coupling.