Dynamic Spin-Polarized Resonant Tunneling in Magnetic Tunnel Junctions

TL;DR

This paper investigates the oscillatory behavior of resistance in magnetic tunnel junctions caused by electron interference effects when tunneling energies match the barrier potential, supported by a quantum mechanical model.

Contribution

It introduces a detailed quantum model of resonant tunneling in magnetic tunnel junctions that explains observed resistance oscillations.

Findings

Resistance oscillates with applied voltage due to electron interference.

The quantum model qualitatively matches experimental data.

Resonant tunneling effects are linked to electron energy and barrier potential.

Abstract

Precisely engineered tunnel junctions exhibit a long sought effect that occurs when the energy of the electron is comparable to the potential energy of the tunneling barrier. The resistance of metal-insulator-metal tunnel junctions oscillates with an applied voltage when electrons that tunnel directly into the barrier's conduction band interfere upon reflection at the classical turning points: the insulator-metal interface, and the dynamic point where the incident electron energy equals the potential barrier inside the insulator. A model of tunneling between free electron bands using the exact solution of the Schroedinger equation for a trapezoidal tunnel barrier qualitatively agrees with experiment.