Spin-dependent transmission through a chain of rings: influence of a periodically modulated spin-orbit interaction strength or ring radius

TL;DR

This paper investigates how spin-orbit interaction and geometric modulation in a chain of quantum rings affect electron transmission, revealing conditions for total opacity and conductance control via interference effects.

Contribution

It introduces an analytical model for spin-dependent transport in a chain of quantum rings with modulated parameters, highlighting the impact of interference on conductance.

Findings

Chain can be totally opaque for certain wave vectors due to destructive spin interference.

Periodic modulation of spin-orbit strength or ring radius widens conductance gaps.

Modulation leads to a nearly binary conductance output, enabling control over electron flow.

Abstract

We study ballistic electron transport through a finite chain of quantum circular rings in the presence of spin-orbit interaction of strength \alpha. For a single ring the transmission and reflection coefficients are obtained analytically and from them the conductance for a chain of rings as a function of \alpha and of the wave vector k of the incident electron. We show that due to destructive spin interferences the chain can be totaly opaque for certain ranges of k the width of which depends on the value of \alpha. A periodic modulation of the strength \alpha or of the ring radius widens up the gaps considerably and produces a nearly binary conductance output.