Singlet-triplet avoided crossings and effective $g$ factor versus spatial orientation of spin-orbit-coupled quantum dots

摘要

We study avoided crossings opened by spin-orbit interaction in the energyspectra of one- and two-electron anisotropic quantum dots in perpendicularmagnetic field. We find that for simultaneously present Rashba and Dresselhausinteractions the width of avoided crossings and the effective $g$ factor dependon the dot orientation within (001) crystal plane. The extreme values of thesequantities are obtained for [110] and [1$\bar{1}$0] orientations of the dot.The width of singlet-triplet avoided crossing changes between these twoorientations by as much as two orders of magnitude. The discussed modulationresults from orientation-dependent strength of the Zeeman interaction whichtends to polarize the spins in the direction of the external magnetic field andthus remove the spin-orbit coupling effects.