Long range phase coherencein double barrier magnetic tunnel junctions with large thick metallic quantum well

TL;DR

This paper demonstrates room-temperature quantum well resonance states in thick Fe layers within magnetic tunnel junctions, revealing high phase coherence due to interface quality, which advances spin-dependent tunneling applications.

Contribution

It provides the first evidence of long-range quantum well resonances in Fe up to 12 nm at room temperature, highlighting the importance of interface strain control.

Findings

Quantum well resonances observed up to 12 nm in Fe at room temperature.

High phase coherence due to homogeneous interface phase shift.

Interface strain critically affects quantum well phase coherence.

Abstract

Double barrier heterostructures are model systems for the study of electron tunneling and discrete energy levels in a quantum well (QW). Until now resonant tunneling phenomena in metallicQW have been observed for limited thicknesses (1-2 nm) under which electron phase coherence is conserved. In the present study we show evidence of QW resonance states in Fe QW up to12 nmthick and at room temperature in fully epitaxial doubleMgAlOxbarrier magnetic tunnel junctions. The electron phase coherence displayed in this QWis of unprecedented quality because ofa homogenous interface phase shift due to the small lattice mismatch at the Fe/MgAlOx interface. The physical understanding of the critical role of interface strain on QW phase coherence will greatly promote the development of the spin-dependent quantum resonant tunneling applications.