I-V curves of Fe/MgO (001) single- and double-barrier tunnel junctions.
Item Type:Journal Article
Citation:J. Peralta-Ramos, A. M. Llois, I. Rungger, and S. Sanvito, I-V curves of Fe/MgO (001) single- and double-barrier tunnel junctions., Phys. Rev. B, 78, 2008, 024430
PhysRevB.78.024430.pdf (PDF) 171.7Kb
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 experiment
Type of material:Journal Article
Series/Report no:Phys. Rev. B
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