Inelastic transport in molecular spin valves: Calculations using the tight-binding Su-Schrieffer-Heeger model

Jean, N.; Sanvito, Stefano

doi:10.1103/physrevb.73.094433

Cited by 13 publications

(9 citation statements)

References 43 publications

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“…When the electron-phonon interaction is weak, or alternatively the molecule is rather short in such a way that polaronic-type of transport is not dominant, then phonon absorption/emission has only the effect of smearing the transmission coefficient. In spin-valves made from transition metals such a smearing is likely to result in a reduction of the spin-polarization of the device and therefore of the GMR 91 . However quantitative predictions are difficult, since also in this case a detailed description of the electronic structure of the electrodes and of the bonding with the molecule is essential.…”

Section: Long Molecules and Phononsmentioning

confidence: 99%

Molecular-Spintronics: The Art of Driving Spin Through Molecules

Sanvito¹,

Rocha²

2006

j comput theor nanosci

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Spintronics is the ability of injecting, manipulating and detecting electron spins into solid state systems. Molecular-electronics investigates the possibility of making electronic devices using organic molecules. Traditionally these two burgeoning areas have lived separate lives, but recently a growing number of experiments have indicated a possible pathway towards their integration. This is the playground for molecular-spintronics, where spin-polarized currents are carried through molecules, and in turn they can affect the state of the molecule. We review the most recent advances in molecular-spintronics. In particular we discuss how a fully quantitative theory for spin-transport in nanostructures can offer fundamental insights into the main factors affecting spin-transport at the molecular level, and can help in designing novel concept devices.

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Section: Long Molecules and Phononsmentioning

confidence: 99%

Molecular-Spintronics: The Art of Driving Spin Through Molecules

Sanvito¹,

Rocha²

2006

j comput theor nanosci

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150

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“…Theoretical studies of inelastic effects in spin flux are available in the literature. [45][46][47] Closely related are questions of heat transport [48][49][50][51] and thermoelectric phenomena [52][53][54][55] in molecular systems. The search for efficient heat-electricity conversion devices has attracted lots of attention to thermoelectric properties of nanosystems.…”

Section: Introductionmentioning

confidence: 99%

Spin seebeck coefficient of a molecular spin pump

Fransson

Galperin

2011

Phys. Chem. Chem. Phys.

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Within a generalized version of previously considered model of a molecular spin pump controlled by an external electric field [J. Fransson and M. Galperin, Phys. Rev. B, 2010, 81, 075311] we discuss thermal properties of such spintronic devices. The spin Seebeck coefficient of a molecular spin pump is introduced, and several possible definitions of a nonequilibrium Seebeck coefficient are discussed. The influence of inelastic effects in spin transport on its thermospintronic characteristics are demonstrated within numerical examples.

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“…The parameters for the model Hamiltonian are chosen for mimicking two systems which have been studied experimentally: H 2 molcules sandwiched between Pt electrodes (H 2 -Pt) 9,31 and Au monatomic chains 10 comprising R atoms (RC's). The parameters for H 2 -Pt are the same as those used by Jean and Sanvito 11 , who previously employed exact scattering theory (EST) to describe phononic effects. In contrast to the SCBA, EST is valid for both strong and weak coupling and therefore it is a good benchmark for the SCBA.…”

Section: Introductionmentioning

confidence: 99%

“…Firstly, they play a role in transport 9,10 by opening new conductance channels through which the itinerant electrons can propagate, and by suppressing the transmission of purely elastic channels 11 . More dramatically, for large electron-phonon coupling the charge carriers become quasi-particles consisting of coupled electrons and phonons 12 .…”

Section: Introductionmentioning

confidence: 99%

“…For elastic transport, when electron-phonon interaction is not considered and the electron-electron interaction is treated at the mean field level, methods of note for predicting the current flowing through devices include the non-equilibrium Green function formalism (NEGF) 13,14,15,16,17 and scattering theory (ST) 12,18,19,20 . Some of these methods have been adapted to include electron-phonon interaction, notably an extension of scattering theory (EST) 11,21,22,23 and the self consistent Born approximation (SCBA) 24,25 within the NEGF formalism. In addition time-dependent methods for describing correlated electron-ion dynamics have been recently proposed 26 .…”

Section: Introductionmentioning

confidence: 99%

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Exploring the limits of the self-consistent Born approximation for inelastic electronic transport

2009

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The non equilibrium Green function formalism is today the standard computational method for describing elastic transport in molecular devices. This can be extended to include inelastic scattering by the so called self-consistent Born approximation (SCBA), where the interaction of the electrons with the vibrations of the molecule is assumed to be weak and it is treated perturbatively. The validity of such an assumption and therefore of the SCBA is difficult to establish with certainty. In this work we explore the limitations of the SCBA by using a simple tight-binding model with the electron-phonon coupling strength α chosen as a free parameter. As model devices we consider Au mono-atomic chains and a H2 molecule sandwiched between Pt electrodes. In both cases our self-consistent calculations demonstrate a breakdown of the SCBA for large α and we identify a weak and strong coupling regime. For weak coupling our SCBA results compare closely with those obtained with exact scattering theory. However in the strong coupling regime large deviations are found. In particular we demonstrate that there is a critical coupling strength, characteristic of the materials system, beyond which multiple self-consistent solutions can be found depending on the initial conditions in the simulation. We attribute these features to the breakdown of the perturbative expansion leading to the SCBA.

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Inelastic transport in molecular spin valves: Calculations using the tight-binding Su-Schrieffer-Heeger model

Cited by 13 publications

References 43 publications

Molecular-Spintronics: The Art of Driving Spin Through Molecules

Molecular-Spintronics: The Art of Driving Spin Through Molecules

Spin seebeck coefficient of a molecular spin pump

Exploring the limits of the self-consistent Born approximation for inelastic electronic transport

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