Spin coherence and conductance modulation in mesoscopic structures

A simple theory of the quantum interference due to spin coherence and Larmor procession of the electron spin is proposed. A spin ballistic regime in a loop structure is assumed, where the phase relaxation length for the spin part of the wave function (Lphi(e)) is much greater than the relaxation length for the orbital part (Lphi(s)). In the presence of additional magnetic field, the spin part of the electron's wave function acquires a phase shift due to additional spin precession about that field. If also the structure length L is chosen such that (formula available in paper), it is possible to wash out the quantum interference related to the phase coherence of the orbital part of the wave function, retaining at the same time that related to the phase coherence of the spin part, to reveal the corresponding conductance oscillations. It is also emphasized that strong modulation of the conductance of the structure could be achieved in this way.