Electric and Magnetic Gating of Rashba-Active Weak Links

TL;DR

This paper demonstrates how combining a Zeeman field with Rashba spin-orbit interaction in a one-dimensional weak link can generate controllable spin and charge currents, with potential applications in spintronics.

Contribution

It reveals that a Zeeman field combined with Rashba SOI can produce a nonzero spin current and oscillating charge/spin currents, enabling electric and magnetic control in weak links.

Findings

Zeeman field with Rashba SOI generates spin current.

Charge and spin currents oscillate with wire length.

Measuring magnetoresistance reveals SOI strength.

Abstract

In a one-dimensional weak-link wire the spin-orbit interaction (SOI) alone cannot generate a nonzero spin current. We show that a Zeeman field acting in the wire in conjunction with the Rashba SOI there does yield such a current, whose magnitude and direction depend on the direction of the field. When this field is not parallel to the effective field due to the SOI, both the charge and the spin currents oscillate with the length of the wire. Measuring the oscillating anisotropic magnetoresistance can thus yield information on the SOI strength. These features are tuned by applying a magnetic and/or an electric field, with possible applications to spintronics.