Zitterbewegung of Spin Split Electrons

Abstract

We describe the trembling motion of conduction-band electrons in solids. The effect originates from the fact that, in the presence of the Rashba/Dresselhaus spin–orbit coupling and the Zeeman splitting, the electron velocity is not a conserved quantity and contains a contribution oscillating at the frequency determined by the spin gap. The phenomenon is similar to the Zitterwebegung of relativistic particles. Trembling motion of individual electrons can be phase-synchronized by initializing the electrons in the same spin states and detected as a macroscopic high-frequency electric current, which is maintained in the system until the electron spin coherence is lost. We also show that the amplitude of such a coherent Zitterbewegung current is increased when its frequency matches the plasmon frequency.