On the environmental decoherence and spin interference in mesoscopic loop structures

TL;DR

This paper investigates how environmental decoherence mechanisms affect spin phase relaxation and quantum interference in mesoscopic loop structures, revealing conditions for observing spin-related conductance oscillations despite orbital decoherence.

Contribution

It introduces the concept of a 'spin ballistic' regime where spin coherence persists longer than orbital coherence, enabling spin interference effects to be observed.

Findings

Spin ballistic regime is possible with longer spin phase relaxation length.

Quantum interference related to orbital phase can be suppressed while spin interference remains.

Conditions for observing spin interference oscillations despite orbital decoherence are identified.

Abstract

Mechanisms of 'environmental decoherence' such as surface scattering, Elliot-Yafet process and precession mechanisms, as well as their influence on the spin phase relaxation are considered and compared. It is shown that the 'spin ballistic' regime is possible, when the phase relaxation length for the spin part of the wave function (WF)is much greater than the phase relaxation length for the 'orbital part'. In the presence of an additional magnetic field, the spin part of the electron's WF acquires a phase shift due to additional spin precession about that field. If the structure length is chosen to be greater than the phase relaxation length for the 'orbital part' and less than the phase relaxation length for the spin part of WF, it is possible to 'wash out' the quantum interference related to the phase coherence of the 'orbital part' of the WF, retaining at the same time that related to the phase coherence of the spin part and, hence, to reveal corresponding conductance oscillations.