Title :
Spin filtering in a quantum ring with Rashba coupling
Author :
Tanatar, B. ; Moldoveanu, V.
Author_Institution :
Dept. of Phys., Bilkent Univ., Ankara, Turkey
Abstract :
We study the effect of Rashba spin-orbit coupling on the spin interference in a non-interacting one-dimensional ring connected to two lead theoretically within the non-equilibrium Greens´ function formalism. We compute the charge and spin currents and analyze their Aharonov-Bohm oscillations. The geometry of the system is conveniently described by the angle ¿ between the two leads. We show that for ¿=180° (i.e for symmetrically coupled leads) a good filtering of up or down spin orientation is obtained around half-integer multiples of ¿/¿0. These particular flux values correspond to degeneracy points for clockwise and counter-clockwise propagating state related to the same spin orientation in the local spin frame of the ring. In contrast, for the asymmetric coupling, i.e., ¿=135° the filter efficiency is maximum around integer multiples of ¿/¿0. The numerical results suggest that the spin filtering is obtained when the clockwise or counter-clockwise states interfere destructively. The spin filtering regime is stable against variations of the bias applied on the system.
Keywords :
Aharonov-Bohm effect; Green´s function methods; quantum interference phenomena; spin-orbit interactions; Aharonov-Bohm oscillations; Rashba spin-orbit coupling; asymmetric coupling; charge current; counter-clockwise propagating state; degeneracy points; flux values; local spin frame; nonequilibrium Greens´ function formalism; noninteracting one-dimensional ring; quantum ring; spin current; spin filtering; spin interference; spin orientation; Clocks; Couplings; Electrons; Elementary particle vacuum; Filtering; Filters; Interference; Magnetic fields; Magnetic separation; Quantum mechanics;
Conference_Titel :
Nanoelectronics Conference (INEC), 2010 3rd International
Conference_Location :
Hong Kong
Print_ISBN :
978-1-4244-3543-2
Electronic_ISBN :
978-1-4244-3544-9
DOI :
10.1109/INEC.2010.5425177