I-V curves of Fe/MgO (001) single- and double-barrier tunnel junctions

Abstract

In this work, we calculate with ab initio methods the current-voltage characteristics for ideal single- and double-barrier Fe/MgO (001) magnetic tunnel junctions. The current is calculated in the phase-coherent limit by using the recently developed SMEAGOL code, combining the nonequilibrium Green function formalism with density-functional theory. In general we find that double-barrier junctions display a larger magnetoresistance, which decays with bias at a slower pace than their single-barrier counterparts. This is explained in terms of enhanced spin filtering from the middle Fe layer sandwiched in between the two MgO barriers. In addition, for double-barrier tunnel junctions, we find a well defined peak in the magnetoresistance at a voltage of V=0.1 V. This is the signature of resonant tunneling across a majority quantum well state. Our findings are discussed in relation to recent experiments.

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Cited by in corpus (5)

• Tunneling in double barrier junctions with 'hot spots'
• Dynamics of optical excitations in a Fe/MgO(001) heterostructure from time-dependent density functional theory
• Interface-related magnetic and vibrational properties in Fe/MgO heterostructures from nuclear resonant spectroscopy and first-principles calculations
• Anisotropic carrier dynamics in a laser-excited Fe${}_1$/(MgO)${}_3$(001) heterostructure from real-time time-dependent DFT
• Transmission spectra of Fe/MgO (001) double-barrier tunnel junctions at finite bias