Eur. Phys. J. B 83, 69-75 (2011)
https://doi.org/10.1140/epjb/e2011-10648-6

Nearly noninvasive readout and manipulation of spin in double quantum dot using spin bias

¹ Department of Physics, and Center of Theoretical and Computational Physics, the University of Hong Kong, Hong Kong, P.R. China
² Department of Physics, Tsinghua University, Beijing, 100084, P.R. China

Received: 25 August 2010
Revised: 11 February 2011
Published online: 12 September 2011

Abstract

Dynamics of two quantum dots coupled to electrodes with spin bias is investigated theoretically by means of the master equations. The two dots are coupled via exchange interaction. When the exchange interaction is much smaller than the lead-dot 2 coupling and dot 2 is under a symmetric spin bias, an initially fully polarized electron spin in dot 1 undergoes an oscillation with ignorable attenuation. Meanwhile, the direction of charge current flowing through dot 2 oscillates in the same period as that of the spin in dot 1. This allows to reverse or nearly noninvasively read out the spin in dot 1, by switching on and off the exchange interaction for a duration of half-integer or integer periods of the oscillation, respectively.