Spin transport through a quantum network: Effects of Rashba spin orbit interaction and Aharonov-Bohm flux

Abstract: We address spin dependent transport through an array of diamonds in the presence of Rashba spin-orbit (SO) interaction where each diamond plaquette is penetrated by an Aharonov-Bohm (AB) flux $\phi$. The diamond chain is attached symmetrically to two semi-infinite one-dimensional non-magnetic metallic leads. We adopt a single particle tight-binding Hamiltonian to describe the system and study spin transport using Green's function formalism. After presenting an analytical method for the energy dispersion relation of an infinite diamond chain in the presence of Rashba SO interaction, we study numerically the conductance-energy characteristics together with the density of states of a finite sized diamond network. At the typical flux $\phi=\phi_0/2$, a delocalizing effect is observed in the presence of Rashba SO interaction, and, depending on the specific choices of SO interaction strength and AB flux the quantum network can be used as a spin filter. Our analysis may be inspiring in designing spintronic devices.