Spin Quantum Tunneling in Single Molecular Magnets: Fingerprints in Transport Spectroscopy of Current and Noise

Romeike, C.; Wegewijs, M. R.; Schoeller, Herbert

doi:10.1103/physrevlett.96.196805

Cited by 94 publications

(20 citation statements)

References 29 publications

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“…2. Similar effects, although of a different physical origin, have already been observed for charge-dependent oscillator frequencies, 24 as fake resonances in single-molecule magnets, 25 in scanning tunnel microscope measurements, 11 or with many-particle resonances in quantum dots. 21,26 …”

Section: B Backscatteringsupporting

confidence: 61%

Nonmonotonic Fano factor and backscattering effects in single-molecule junctions

Schultz

2010

Phys. Rev. B

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Rate equations are a common tool to describe the transport properties of weakly coupled single-molecule junctions. Here, we study the physics of the Anderson-Holstein model at a single vibronic resonance. We derive conditions on the Franck-Condon factors that the resonance increases or decreases the stationary current thus causing negative differential conductance. The role of backscattering of charge at vibronic resonances is also investigated. In strongly asymmetrically coupled devices backscattering causes the resonance to split into two. In symmetrically coupled devices, the Fano factor shows nonmonotonicities, which are related to correlations of forward and backward scattering of charge.

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Section: B Backscatteringsupporting

confidence: 61%

Nonmonotonic Fano factor and backscattering effects in single-molecule junctions

Schultz

2010

Phys. Rev. B

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“…25,[35][36][37][38][39][40][41][42][43][44][45][46] The systems studied include magnetic grains, 39,47 semiconductor 37 and Mn-doped quantum dots, 35,44 and molecular magnets and magnetic molecules. [40][41][42][43]48 Here we can model the current driven dynamics of a quantum spin whose Hamiltonian parameters are accurately known from experiments, 11 making it possible to compare successfully theory and experiment.…”

Section: Introductionmentioning

confidence: 99%

Spin dynamics of current-driven single magnetic adatoms and molecules

2010

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A scanning tunneling microscope can probe the inelastic spin excitations of a single magnetic atom in a surface via spin-flip assisted tunneling in which transport electrons exchange spin and energy with the atomic spin. If the inelastic transport time, defined as the average time elapsed between two inelastic spin flip events, is shorter than the atom spin-relaxation time, the scanning tunnel microscope ͑STM͒ current can drive the spin out of equilibrium. Here we model this process using rate equations and a model Hamiltonian that describes successfully spin-flip-assisted tunneling experiments, including a single Mn atom, a Mn dimer, and Fe Phthalocyanine molecules. When the STM current is not spin polarized, the nonequilibrium spin dynamics of the magnetic atom results in nonmonotonic dI / dV curves. In the case of spin-polarized STM current, the spin orientation of the magnetic atom can be controlled parallel or antiparallel to the magnetic moment of the tip. Thus, spin-polarized STM tips can be used both to probe and to control the magnetic moment of a single atom.

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“…A general and now standard approach to calculating the conductance spectra of the various possible magnetic nanostructures is that of combining a master equation solver for the quantum transport problem with a model Hamiltonian describing the magnetic interaction. 9 This is an intrinsic many-body approach, which in principle contains all the ingredients needed for solving the problem, once the various transfer rates are known. As such it usually requires a large number of parameters to be predictive.…”

Section: Introductionmentioning

confidence: 99%

Spin-flip inelastic electron tunneling spectroscopy in atomic chains

2011

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We present a theoretical study of the spin transport properties of monoatomic magnetic chains with a focus on the spectroscopical features of the I -V curve associated with spin-flip processes. Our calculations are based on the s-d model for magnetism with the electron transport treated at the level of the nonequilibrium Green's function formalism. Inelastic spin-flip scattering processes are introduced perturbatively via the first Born approximation, and an expression for the associated self-energy is derived. The computational method is then applied to describe the I -V characteristics and its derivatives of one-dimensional chains of Mn atoms, and the results are then compared to available experimental data. We find a qualitative and quantitative agreement between the calculated and the experimental conductance spectra. Significantly we are able to describe the relative intensities of the spin excitation features in the I -V curve, by means of a careful analysis of the spin transition selection rules associated with the atomic chains.

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Spin Quantum Tunneling in Single Molecular Magnets: Fingerprints in Transport Spectroscopy of Current and Noise

Cited by 94 publications

References 29 publications

Nonmonotonic Fano factor and backscattering effects in single-molecule junctions

Nonmonotonic Fano factor and backscattering effects in single-molecule junctions

Spin dynamics of current-driven single magnetic adatoms and molecules

Spin-flip inelastic electron tunneling spectroscopy in atomic chains

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