Magnetic focusing of charge carriers from spin-split bands: Semiclassics of a Zitterbewegung effect

摘要

We present a theoretical study of the interplay between cyclotron motion andspin splitting of charge carriers in solids. While many of our results applymore generally, we focus especially on discussing the Rashba model describingelectrons in the conduction band of asymmetric semiconductor heterostructures.Appropriate semiclassical limits are distinguished that describe varioussituations of experimental interest. Our analytical fomulae, which take fullaccount of Zeeman splitting, are used to analyse recent magnetic-focusing data.Surprisingly, it turns out that the Rashba effect can dominate the splitting ofcyclotron orbits even when the Rashba and Zeeman spin-splitting energies are ofthe same order. We also find that the origin of spin-dependent cyclotron motioncan be traced back to Zitterbewegung-like oscillatory dynamics of chargecarriers from spin-split bands. The relation between the two phenomena isdiscussed, and we estimate the effect of Zitterbewegung-related corrections tothe charge carriers' canonical position.