Ballistic spin-filter transistor

Spin-dependent ballistic transport in a mesoscopic two-dimensional electron system with two metallic ferromagnetic electrodes is studied using the Landauer-Buttiker formalism. Our calculations predict a pronounced spin-valve effect in the ballistic regime for, e.g., Fe on InAs. The origin is spin filtering at the interfaces. In this spintronic device, the magnetoconductance ratio can be controlled via a gate voltage.