General Green’s-function formalism for transport calculations with<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>spd</mml:mi></mml:math>Hamiltonians and giant magnetoresistance in Co- and Ni-based magnetic multilayers

Sanvito, Stefano; Lambert, Colin J.; Jefferson, J. H.; Bratkovsky, A. M.

doi:10.1103/physrevb.59.11936

Cited by 314 publications

(362 citation statements)

References 27 publications

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“…These self-energies depend on energy E and k vector, and they are obtained from spinpolarized calculations of retarded surface Green's functions for the electrodes which are computed using the scheme developed in Ref. 46. The initial magnetic moment of the scattering region is set to 20 B .…”

Section: Computational Methods and Modelmentioning

confidence: 99%

Effects of bonding type and interface geometry on coherent transport through the single-molecule magnetMn12

et al. 2010

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We examine theoretically coherent electron transport through the single-molecule magnet Mn 12 , bridged between Au͑111͒ electrodes, using the nonequilibrium Green's function method and the density-functional theory. We analyze the effects of bonding type, molecular orientation, and geometry relaxation on the electronic properties and charge and spin transport across the single-molecule junction. We consider nine interface geometries leading to five bonding mechanisms and two molecular orientations: ͑i͒ Au-C bonding, ͑ii͒ Au-Au bonding, ͑iii͒ Au-S bonding, ͑iv͒ Au-H bonding, and ͑v͒ physisorption via van der Waals forces. The two molecular orientations of Mn 12 correspond to the magnetic easy axis of the molecule aligned perpendicular ͓hereafter denoted as orientation ͑1͔͒ or parallel ͓orientation ͑2͔͒ to the direction of electron transport. We find that the electron transport is carried by the lowest unoccupied molecular orbital ͑LUMO͒ level in all the cases that we have simulated. Relaxation of the junction geometries mainly shifts the relevant occupied molecular levels toward the Fermi energy as well as slightly reduces the broadening of the LUMO level. As a result, the current slightly decreases at low bias voltage. Our calculations also show that placing the molecule in the orientation ͑1͒ broadens the LUMO level much more than in the orientation ͑2͒ due to the internal structure of the Mn 12 . Consequently, junctions with the former orientation yield a higher current than those with the latter. Among all of the bonding types considered, the Au-C bonding gives rise to the highest current ͑about one order of magnitude higher than the Au-S bonding͒, for a given distance between the electrodes. The current through the junction with other bonding types decreases in the order of Au-Au, Au-S, and Au-H. Importantly, the spin-filtering effect in all the nine geometries stays robust and their ratios of the majority-spin to the minorityspin transmission coefficients are in the range of 10 3 -10 8 . The general trend in transport among the different bonding types and molecular orientations obtained from this study may be applicable to other single-molecule magnets.

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Section: Computational Methods and Modelmentioning

confidence: 99%

Effects of bonding type and interface geometry on coherent transport through the single-molecule magnetMn12

et al. 2010

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“…(6). This approach has been applied with good success with ab-initio calculations of FN interfaces [30][31][32]67 .…”

Section: A Multiscale Approach To Spinmentioning

confidence: 99%

Multiscale approach to spin transport in magnetic multilayers

et al. 2011

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This article discusses two dual approaches to spin transport in magnetic multilayers: a direct, purely quantum, approach based on a Tight-Binding model (TB) and a semiclassical approach (Continuous Random Matrix Theory, CRMT). The combination of both approaches provides a systematic way to perform multi-scales simulations of systems that contain relevant physics at scales larger (spin accumulation, spin diffusion...) and smaller (specular reflexions, tunneling...) than the elastic mean free paths of the layers. We show explicitly that CRMT and TB give consistent results in their common domain of applicability.

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“…The injector and the collector were modeled by heavily doped graphene and the transmission was calculated employing the Green's-function technique of Ref. 22. The graphene nanoribbons are assumed to be perfectly ballistic and infinitely long.…”

Section: Details Of the Numerical Calculationsmentioning

confidence: 99%

Exploring the graphene edges with coherent electron focusing

et al. 2010

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We study theoretically the coherent electron focusing in graphene nanoribbons. Using semiclassical and numerical tight-binding calculations we show that armchair edges give rise to equidistant peaks in the focusing spectrum. In the case of zigzag edges at low magnetic fields one can also observe focusing peaks but with increasing magnetic field a more complex interference structure emerges in the spectrum. This difference in the spectra can be observed even if the zigzag edge undergoes structural reconstruction. Therefore transverse electron focusing can help in the identification and characterization of the edge structure of graphene samples.

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General Green’s-function formalism for transport calculations withspdHamiltonians and giant magnetoresistance in Co- and Ni-based magnetic multilayers

Cited by 314 publications

References 27 publications

Effects of bonding type and interface geometry on coherent transport through the single-molecule magnetMn12

Effects of bonding type and interface geometry on coherent transport through the single-molecule magnetMn12

Multiscale approach to spin transport in magnetic multilayers

Exploring the graphene edges with coherent electron focusing

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