Transport Properties Of Ferromagnet / Insulator / Semiconductor Hybrid Structure

Based on Slonczewski free electron model, we investigate transport properties of spin-polarized electrons tunneling through ferromagnetic /insulator/semiconductor/insulator/ferromagnetic double junctions in the presence of the Rashba spin-orbit interaction. The significant quantum size, quantum coherence, ballistic transport, and Rashba spin-orbit interaction are considered simultaneously. The insulator in this work is a finite length layer, not a Delta potential.In this paper, we deduce a formula of the transmission coefficient using the transfer matrix method for the double tunnel junction and investigate the transport properties vs. the Rashba spin-orbit coupling strength, the length of the semiconductor, and the length of the insulator. The results of the numerical calculation indicate that:The transmission probability shows typical resonant tunnel properties. When the energy of the incident electron satisfies the condition of resonant tunneling, the transmission coefficient will reach its maximum.With the length of the semiconductor varying, the transmission coefficient, the tunnel magnetoresistance, and the spin-polarization exhibit oscillating behavior with the period ofπ/k.As the Rashba spin-orbit coupling strength or the length of the semiconductor varied, the angleΦoriginated from the formula of transmission coefficient will change, as a result, the transport properties are modified considerably.The insulator barrier affects the half width of the transmission resonant peaks. As the height or the width of the rectangular barrier potential increase, the half width of the tunnel resonant peaks decreases obviously.