Spin motion of photoelectrons

Henk, J.; Bose, P.; Michael, Th.; Bruno, P.

doi:10.1103/physrevb.68.052403

Cited by 26 publications

(35 citation statements)

References 20 publications

(15 reference statements)

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“…Such Rashba splitting was observed via photoemission by LaShell et al. [3] for the L-gap surface state at Au(111) and explained theoretically in terms of a tight-binding model [4] and ab initio electronic structure calculations [5,6], but several studies of the Rashba splitting were published in recent years on Bi(111) and Bi/Ag(111) [7][8][9], as well as on Bi x Pb 1−x /Ag(111), where atomic Bi p-orbitals lead to a more pronounced spin-orbit splitting [10][11][12][13].Describing and controlling the Rashba splitting of surface states is crucial for spintronics applications. The famous Datta-Das transistor relies on the electric tuning of the Rashba splitting [14] and the Rashba splitting is responsible for the spin Hall effect in two dimensions [15] and the anomalous Hall effect [16] as well.…”

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confidence: 81%

Anisotropic Rashba splitting of surface states from the admixture of bulk states: Relativisticab initiocalculations andk⋅pperturbation theory

et al. 2010

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We investigate the surface Rashba effect for a surface of reduced in-plane symmetry. Formulating a k·p perturbation theory, we show that the Rashba splitting is anisotropic, in agreement with symmetry-based considerations. We show that the anisotropic Rashba splitting is due to the admixture of bulk states of different symmetry to the surface state, and it cannot be explained within the standard theoretical picture supposing just a normal-to-surface variation of the crystal potential. Performing relativistic ab initio calculations we find a remarkably large Rashba anisotropy for an unreconstructed Au(110) surface that is in the experimentally accessible range. Metallic surfaces often exhibit Shockley-type surface states located in a relative band gap of the bulk band structure, and forming a two-dimensional electron gas. One of the most intriguing manifestation of spin-orbit coupling (SOC) at surfaces is the splitting of these surface states, known as Rashba splitting [1,2]. Such Rashba splitting was observed via photoemission by LaShell et al. [3] for the L-gap surface state at Au(111) and explained theoretically in terms of a tight-binding model [4] and ab initio electronic structure calculations [5,6], but several studies of the Rashba splitting were published in recent years on Bi(111) and Bi/Ag(111) [7][8][9], as well as on Bi x Pb 1−x /Ag(111), where atomic Bi p-orbitals lead to a more pronounced spin-orbit splitting [10][11][12][13].Describing and controlling the Rashba splitting of surface states is crucial for spintronics applications. The famous Datta-Das transistor relies on the electric tuning of the Rashba splitting [14] and the Rashba splitting is responsible for the spin Hall effect in two dimensions [15] and the anomalous Hall effect [16] as well.The simplest way to understand the origin of the Rashba effect is to take nearly free electrons, confined by a crystal potential, V (r) = V (z), and having a planewave-like wave function, ψ s,k (r) = e ikr φ (z) χ s , with χ s some spinor eigenfunctions, and k the momentum parallel to the surface. The crystal potential V (z) obviously produces an electric field, E, perpendicular to the surface, which, in the presence of spin-orbit interaction leads to the following spin-orbit term in the effective Hamiltonian,called Rashba-Hamiltonian. In Eq. (1), σ i denote the Pauli matrices andis the so-called Rashba parameter. The eigenvalue problem can then easily be solved, resulting in a splitting of the spin-degeneracy of the surface states, ε ± (k) = 2 2m * k 2 ±α R |k| , with m * the effective mass of the surface electrons [4,6]. Clearly, the above dispersion is isotropic in k-space, hence we term it as isotropic Rashba splitting. Although real systems cannot be described in terms of free electrons, and for quantitative estimates of α R the atomic structure of the potential needs be taken into account [8], the structure of the Rashba interaction, Eq. (1), is very robust for surfaces of high point-group symmetry such as C 3v or C 4v [19].The situation is, howe...

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confidence: 81%

Anisotropic Rashba splitting of surface states from the admixture of bulk states: Relativisticab initiocalculations andk⋅pperturbation theory

et al. 2010

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“…30,31 For ideal planar Co 0001 electrodes separated by a vacuum gap, calculations based on the density-functional theory show a TMR of 260%. 32 In supported two-dimensional nanostructures the band narrowing due to the reduced symmetry and the polarization of the substrate could lead to even higher TMR value. Second, SP-STM experiments under UHV conditions warrant the absence of inelastic scattering from impurities or defects at the interfaces and in the amorphous barrier.…”

Section: Applied Physics Lettersmentioning

confidence: 99%

High tunnel magnetoresistance in spin-polarized scanning tunneling microscopy of Co nanoparticles on Pt(111)

Rusponi

Weiss

Cren

et al. 2005

Applied Physics Letters

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We employ variable-temperature spin-polarized scanning tunneling microscopy in constant current mode to read the magnetic state of monodomain cobalt nanoparticles on Pt 111 . In order to avoid stray fields we use in situ prepared antiferromagnetically Cr coated W tips. The contrast in apparent height between nanoparticles with opposite magnetization is typically z = 0.20± 0.05 Å, but can reach up to 1.1 Å, indicating 80% spin-polarization of the nanoparticles and 850% magnetoresistance of the tip-sample tunnel junction with tip and sample at 300 K and 160 K, respectively. There is no zero-bias anomaly. These results suggest state-selective tunneling which is expected to lead to very high magnetoresistance values.

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“…The total transmittance T (V ) comprises the transmission probabilities in the 'energy window of tunneling' opened by V . 13 Once the potential profile is self-consistently determined, the transmission spectrum from leads L i to L j under the external applied bias, V = µ i − µ j , can be calculated as…”

Section: Computation Of the Conductancementioning

confidence: 99%

First-principles methodology for quantum transport in multiterminal junctions

Saha

Bernholc

et al. 2009

The Journal of Chemical Physics

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We present a generalized approach for computing electron conductance and I-V characteristics in multiterminal junctions from first-principles. Within the framework of Keldysh theory, electron transmission is evaluated employing an O(N) method for electronic-structure calculations. The nonequilibrium Green function for the nonequilibrium electron density of the multiterminal junction is computed self-consistently by solving Poisson equation after applying a realistic bias. We illustrate the suitability of the method on two examples of four-terminal systems, a radialene molecule connected to carbon chains and two crossed carbon chains brought together closer and closer. We describe charge density, potential profile, and transmission of electrons between any two terminals. Finally, we discuss the applicability of this technique to study complex electronic devices.

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Spin motion of photoelectrons

Cited by 26 publications

References 20 publications

Anisotropic Rashba splitting of surface states from the admixture of bulk states: Relativisticab initiocalculations andk⋅pperturbation theory

Anisotropic Rashba splitting of surface states from the admixture of bulk states: Relativisticab initiocalculations andk⋅pperturbation theory

High tunnel magnetoresistance in spin-polarized scanning tunneling microscopy of Co nanoparticles on Pt(111)

First-principles methodology for quantum transport in multiterminal junctions

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