Vibron-assisted spin relaxation at a metal/organic interface

Droghetti, Andrea; Rungger, Ivan; Cinchetti, Mirko; Sanvito, Stefano

doi:10.1103/physrevb.91.224427

Cited by 7 publications

(6 citation statements)

References 42 publications

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“…In contrast, off-site scattering could be given by vibron-assisted spin-flips as described recently in ref. 56 . The latter process does not need any source of spin-depolarization at the molecular site, as the spin-flip processes are mediated by the Co substrate.…”

Section: Discussionmentioning

confidence: 99%

Dynamic spin filtering at the Co/Alq3 interface mediated by weakly coupled second layer molecules

et al. 2016

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Spin filtering at organic-metal interfaces is often determined by the details of the interaction between the organic molecules and the inorganic magnets used as electrodes. Here we demonstrate a spin-filtering mechanism based on the dynamical spin relaxation of the long-living interface states formed by the magnet and weakly physisorbed molecules. We investigate the case of Alq3 on Co and, by combining two-photon photoemission experiments with electronic structure theory, show that the observed long-time spin-dependent electron dynamics is driven by molecules in the second organic layer. The interface states formed by physisorbed molecules are not spin-split, but acquire a spin-dependent lifetime, that is the result of dynamical spin-relaxation driven by the interaction with the Co substrate. Such spin-filtering mechanism has an important role in the injection of spin-polarized carriers across the interface and their successive hopping diffusion into successive molecular layers of molecular spintronics devices.

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Section: Discussionmentioning

confidence: 99%

Dynamic spin filtering at the Co/Alq3 interface mediated by weakly coupled second layer molecules

et al. 2016

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“…But molecules also vibrate. In particular, in magnetic molecules the interplay of vibrational modes, or vibrons, with the spin degrees of freedom is known to impact the spin lifetime [4][5][6]. Since vibrational modes can couple to the electric charge, producing vibron-assisted electron excitations in transport [7][8][9], expectations are that similar effects should be also observed with the electronic spin [10,11].Concerning this last point, experimental work has predominantly focused on a well-known spin-related manybody effect, the Kondo effect.…”

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confidence: 99%

Vibron-assisted spin excitation in a magnetically anisotropic molecule

et al. 2020

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The ability to electrically-drive spin excitations in molecules with magnetic anisotropy is key for high-density storage and quantum-information technology. Electrons, however, also tunnel via the vibrational excitations unique to a molecule. The interplay of spin and vibrational excitations offers novel routes to study and, ultimately, electrically manipulate molecular magnetism. Here we use a scanning tunneling microscope to electrically induce spin and vibrational excitations in a single molecule consisting of a nickelocene magnetically coupled to a Ni atom. We evidence a vibron-assisted spin excitation at an energy one order of magnitude higher compared to the usual spin excitations of nickelocene and explain it using first-principles calculations that include electron correlations. Furthermore, we observe that spin excitations can be quenched by modifying the Ni-nickelocene coupling. Our study suggests that nickelocene-based complexes constitute a model playground for exploring the interaction of spin and vibrations in the electron transport through single magnetic molecules.Magnetic molecules are potential candidates for information-storing technology [1], molecular spintronics [2] and quantum computing [3], provided that their axial magnetic anisotropy DS 2 z ensures a magnetic bistability among longlived magnetic states. But molecules also vibrate. In particular, in magnetic molecules the interplay of vibrational modes, or vibrons, with the spin degrees of freedom is known to impact the spin lifetime [4][5][6]. Since vibrational modes can couple to the electric charge, producing vibron-assisted electron excitations in transport [7][8][9], expectations are that similar effects should be also observed with the electronic spin [10,11].Concerning this last point, experimental work has predominantly focused on a well-known spin-related manybody effect, the Kondo effect. The electron-vibron interaction in Kondo molecules was shown to produce satellite Kondo resonances in the differential conductance spectra at the bias of the vibron's excitation energy [12][13][14]. These resonances were ascribed to tunneling electrons that have their spin flipped when elastically scattering off the molecular spin, but with sufficient energy to activate a vibrational mode in the molecule [15]. The question arises whether a similar mechanism is also possible with other spin scattering mechanisms that magnetically excite a molecule such as inelastic scattering involving magnetic anisotropy [16]. These so-called spin excitations show great potential in view of an all-electrical manipulation of the molecular spin [17,18].Here, we use scanning tunneling microscopy (STM) to demonstrate the presence of a combined vibrational-spin excitation in a single nickelocene molecule [Ni(C 5 H 5 ) 2 , see Fig. 1(d); noted Nc hereafter] coupled to a Ni atom. Nickelocene is a spin S = 1 molecule of the metallocene family with magnetic anisotropy, where spin excitations produce a sizable increase of the electronic transport [19]. We show that the o...

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“…Over the years, intense efforts have been devoted to prove spin-injection from ferromagnetic electrodes into an OSC and to investigate the key role played by the interfaces [11][12][13][14][15][16][17][18][19][20][21][22]. Some experiments have indicated that the injection of spin-polarized charge carriers into molecular orbitals can be achieved both electrically [9,10] and optically [11].…”

Section: Introductionmentioning

confidence: 99%

Impurity band magnetism in organic semiconductors

Droghetti

Sanvito

2019

Phys. Rev. B

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Recent experiments and theoretical studies have proposed that spin-transport in organic semiconductors, in particular in Alq 3 , may occur in an impurity band. Here we model the electronic and magnetic properties of such an impurity band by treating the effect of disorder in a numerically accurate way. The calculations are carried out by solving the Anderson-Hubbard model within the mean-field approximation and by accounting for magnetic excitations via the Bethe-Salpeter equation. We find that some impurities form clusters where electrons are delocalized, while others develop localized magnetic moments, which are antiferromagnetically correlated. The excitations of these correlated magnetic moments are spin waves, which can enable spin transport.

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Vibron-assisted spin relaxation at a metal/organic interface

Cited by 7 publications

References 42 publications

Dynamic spin filtering at the Co/Alq3 interface mediated by weakly coupled second layer molecules

Dynamic spin filtering at the Co/Alq3 interface mediated by weakly coupled second layer molecules

Vibron-assisted spin excitation in a magnetically anisotropic molecule

Impurity band magnetism in organic semiconductors

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