Efficient Spin Transitions in Inelastic Electron Tunneling Spectroscopy

Lorente, Nicolás; Gauyacq, J.P.

doi:10.1103/physrevlett.103.176601

Cited by 116 publications

(198 citation statements)

References 33 publications

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“…Here, we show that the correlated spin nature of AFM quantal chains is at the origin of the transition between Néel states and, from this, we deduce the behavior of the switching rate with respect to applied bias and chain size. Hence, our theory shows that the ability of switching states is intrinsic to AFM-correlated atomic systems.One Fe atom on CuN=Cuð100Þ is characterized by an S ¼ 2 spin [18,19] with a large magnetic anisotropy [18]. …”

mentioning

confidence: 99%

“…One Fe atom on CuN=Cuð100Þ is characterized by an S ¼ 2 spin [18,19] with a large magnetic anisotropy [18].…”

mentioning

confidence: 99%

“…Here, we use S T ¼ 5 2 revealed as the dominant tunneling channel by density functional theory studies in Ref. [19] for an isolated Fe atom on CuN=Cuð100Þ. The scattering amplitude between the chain magnetic states is then obtained as the matrix element of the amplitude (3) between initial jii ¼ j i ij i i and final jfi ¼ j f ij f i states written as direct products of the scattering electron state of spin and the chain state j i, the eigenstate of Hamiltonian (2).…”

mentioning

confidence: 99%

“…We describe the magnetic excitation during tunneling using the strong-coupling approach of Ref. [19] in which the electron strongly interacts with the atom it tunnels through. Let us consider the system schematized in Fig.…”

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Correlation-Mediated Processes for Electron-Induced Switching between Néel States of Fe Antiferromagnetic Chains

et al. 2013

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The controlled switching between two quasistable Néel states in adsorbed antiferromagnetic Fe chains has recently been achieved by Loth et al. [Science 335, 196 (2012)] using tunneling electrons from an STM tip. In order to rationalize their data, we evaluate the rate of tunneling electron-induced switching between the Néel states. Good agreement is found with the experiment, permitting us to identify three switching mechanisms: (i) The search for nanoscale electronic devices has prompted intense research in the field of nanomagnetism. The use of spin as the information conveying entity has stirred much excitement due to its extraordinary properties of information storage, speed, and low-energy consumption [1][2][3]. Miniaturization is quickly proceeding, reaching very small domain-wall devices [4], atomic-size devices [5], and the realm of molecular devices [2,[6][7][8][9]. Among all these possibilities, antiferromagnetically (AFM) coupled devices have recently received a lot of attention. The AFM characteristics make these devices very well fitted for quantum computation since they naturally involved entangled states [10,11]. Moreover, the storage in AFM devices is particularly robust due to the lack of a total magnetic moment. However, this robustness has deterred their use because changing their magnetic state becomes difficult [12].Recently, Loth and co-workers succeeded in controllably switching the spin states of AFM atomic chains [12]. Two quasistable Néel states, exhibiting alternating spin directions on the atoms along the chain, were evidenced in Fe chains adsorbed on a CuN=Cuð100Þ surface. Loth and co-workers showed that the Néel states can be switched by tunneling electrons injected from a polarized scanning tunneling microscope (STM) tip into one of the atoms of the chain. This demonstrated the possibility of storing information on the atomic-scale antiferromagnet. Theoretical predictions show that writing and reading spin states entail fundamental problems associated with the quantum nature of the process [13]. Spin manipulation by tunneling electrons has been pictured as due to a spintorque mechanism where spin angular momentum from the electron is transferred into the atomic spin system [14][15][16]. However, due to the lack of magnetic moment in AFM systems, spin manipulation must follow a different mechanism. Unavoidably, spin manipulations and excitations are closely related [17]. Indeed, switching between Néel states has been experimentally associated with overcoming an activation energy [12]. However, in the case of degenerate Néel states, resonant transitions should be expected. Hence, the experimental data raise many questions regarding the possibility of resonant switching, the efficiency of activated switching, the nature of the involved excitations, and the physics at play in AFM spin torque. In summary, a complete view of the switching process is missing.In this Letter, we reveal the switching mechanisms at play in the experiment of Ref. [12]. The mechanisms turn out to be rich and ...

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confidence: 99%

“…One Fe atom on CuN=Cuð100Þ is characterized by an S ¼ 2 spin [18,19] with a large magnetic anisotropy [18].…”

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Correlation-Mediated Processes for Electron-Induced Switching between Néel States of Fe Antiferromagnetic Chains

et al. 2013

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“…3 The five unpaired electrons in the Mn 3d shell suggest a S = 5/2 ground state, as confirmed both by experiments and theory. 14,24 The spin-spin exchange interaction between two Mn atoms is antiferromagnetic and has an estimated value of J dd = 6.2 meV. As a result, the ground state of the dimer is a singlet (total spin S = 0).…”

Section: A Nonequilibrium Populationmentioning

confidence: 99%

Bias asymmetry in the conductance profile of magnetic ions on surfaces probed by scanning tunneling microscopy

2012

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The conductance profiles of magnetic transition-metal atoms, such as Fe, Co, and Mn, deposited on surfaces and probed by a scanning tunneling microscope (STM), provide detailed information on the magnetic excitations of such nanomagnets. In general, the profiles are symmetric with respect to the applied bias. However, a set of recent experiments has shown evidence for inherent asymmetries when either a normal or a spin-polarized STM tip is used. In order to explain such asymmetries, here we expand our previously developed perturbative approach to electron-spin scattering to the spin-polarized case and to the inclusion of out of equilibrium spin populations. In the case of a magnetic STM tip, we demonstrate that the asymmetries are driven by the nonequilibrium occupation of the various atomic spin levels, an effect that is reminiscent of electron spin transfer. In contrast, when the tip is not spin polarized, such a nonequilibrium population cannot be built up. In this circumstance, we propose that the asymmetry simply originates from the transition metal ion density of states and from the uneven electronic coupling between the scattering magnetic atoms and both the tip and the substrate. These effects are included in the formalism as a nonvanishing real component to the spin-scattering self-energy.

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Controlled Manipulation of Single Atoms and Small Molecules Using the Scanning Tunneling Microscope

Morgenstern¹,

Lorente²,

Rieder³

2016

Surface and Interface Science

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Efficient Spin Transitions in Inelastic Electron Tunneling Spectroscopy

Cited by 116 publications

References 33 publications

Correlation-Mediated Processes for Electron-Induced Switching between Néel States of Fe Antiferromagnetic Chains

Correlation-Mediated Processes for Electron-Induced Switching between Néel States of Fe Antiferromagnetic Chains

Bias asymmetry in the conductance profile of magnetic ions on surfaces probed by scanning tunneling microscopy

Controlled Manipulation of Single Atoms and Small Molecules Using the Scanning Tunneling Microscope

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