Abstract
Spin currents may be generated by applying bias voltages V to the nanostructures even in the absence of spin-active ferromagnetic interfaces. Most theoretical proposals concentrate on a concrete spin–orbit interaction and on the disorder-averaged effect. It remains underappreciated that any spin–orbit interaction produces random spin currents with a typical amplitude not affected by disorder. This work addresses such mesoscopic fluctuations of spin currents for a generic model of a nanostructure where several quantum connectors meet in a single node. The analysis is performed in the framework of recently developed quantum circuit theory of GQ corrections and reveals four distinct mechanisms of spin current fluctuations. The results are elaborated for simple models of tunnel and ballistic connectors.
Highlights
In recent years, considerable theoretical and experimental work has been aimed at the controlled manipulation of electron spin in solid state systems, a field commonly referred to as spintronics [1]
We see that the spin current fluctuations are contributed by three distinct mechanisms corresponding to three terms (24), (25) and (26)
Inspecting its form, we find that the fluctuating spin currents in each transport channel are always proportional to the corresponding filling factor drops and apart from the (1 − Ti ) factor, to the corresponding charge currents
Summary
Considerable theoretical and experimental work has been aimed at the controlled manipulation of electron spin in (nanoscale) solid state systems, a field commonly referred to as spintronics [1]. It remains underappreciated that even for completely chaotic scattering there must be significant mesoscopic fluctuations of spin currents They are governed by the same quantum interference mechanism as the celebrated universal conductance fluctuations [12] and must be of the same scale. We theoretically investigate the mesoscopic fluctuations of spin currents for multi-terminal nanostructures assuming sufficient isotropization of the electron distribution function that allows all geometric effects to be disregarded. This means that after averaging over random phase shifts/impurity positions there is no net spin effect and the system is SU (2) invariant with respect to rotations in spin space. The results derived and discussed in the article conform to these general expectations and give details of spin current fluctuations and their correlations for connectors of low and high transmission
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
