Origin of the surface-state band-splitting in ultrathin Bi films: from a Rashba effect to a parity effect

Using first-principles methods based on density-functional theory, we investigate the spin relaxation in W(001) ultrathin films. Within the framework of the Elliott-Yafet theory, we calculate the spin mixing of the Bloch states and we explicitly consider spin-flip scattering off self-adatoms. At small film thicknesses, we find an oscillatory behavior of the spin-mixing parameter and relaxation rate as a function of the film thickness, which we trace back to surface-state properties. We also analyze the Rashba effect experienced by the surface states and discuss its influence on the spin relaxation. Finally, we calculate the anisotropy of the spin-relaxation rate with respect to the polarization direction of the excited spin population relative to the crystallographic axes of the film. We find that the spin-relaxation rate can increase by as much as 27% when the spin polarization is directed out of plane, compared to the case when it is in plane. Our calculations are based on the multiple-scattering formalism of the Korringa-Kohn-Rostoker Green-function method.

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“…(1). 51 We introduce an intuitive view of our approach by means of a schematic energy level diagram in Fig. 5 (top).…”

Section: Rashba-character Of Surface Statesmentioning

confidence: 99%

Spin relaxation and the Elliott-Yafet parameter in W(001) ultrathin films: Surface states, anisotropy, and oscillation effects

et al. 2013

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“…Bismuth (Bi) has received in-depth attention in the last years due to its interesting electronic properties [1][2][3][4] . On one hand, the strong spin-orbit coupling present in this material is responsible for its peculiar band structure, characterized by a highly anisotropic Fermi surface [5][6][7] .…”

Section: Introductionmentioning

confidence: 99%

Mixed Effects of the Atomic Arrangement and Surface Chemistry on the Electrodeposition of Bi Thin Films on n-GaAs Substrates

et al. 2016

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We have studied the electrodeposition of Bi thin films on two GaAs orientations with different atomic arrangement and chemical composition, (110) and (111)B. The electrochemical properties of each substrate have been analyzed by means of cyclic voltammetries and current transients. Then, x-ray diffraction has been used to determine the crystal structure and quality of the Bi films, and atomic force microscopy images have provided information about the surface morphology. Finally, the Bi/GaAs interface has been electrically characterized by means of capacitance-voltage and current-voltage curves. In this study, we have been able to discriminate between the effect of surface chemistry and the arrangement of surface atoms. The former has a direct effect on the reduction process of Bi(III) ions and on the electrical properties of the Bi/GaAs interface, whereas the atoms arrangement at the substrate surface determines the texture and morphology of the Bi films.3

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“…Bismuth (Bi) is a group V semimetal with a large SOI due to the heavy mass of the Bi atom; therefore, the surface of Bi crystals is an ideal system to observe a strong Rashba effect 6 . Angle-resolved photoemission spectroscopy (APRES) experiments have been reported for the Bi surface accompanied with first-principles band calculations [7][8][9][10][11][12][13][14][15][16][17][18][19] . The surface states have a hexagonal electron pocket around theΓ point and six-fold hole pockets 7,9,10,16,19 Firstprinciples band calculations showed that these two surface states are spin-split bands 8,10 , and this Rashba splitting has been confirmed experimentally [12][13][14] .…”

mentioning

confidence: 99%

Tight-binding theory of surface spin states on bismuth thin films

et al. 2016

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The surface spin states for bismuth thin films are investigated using an sp 3 tight-binding model. The model explains most experimental observations using angle-resolved photoemission spectroscopy, including the Fermi surface, the band structure with Rashba spin splitting, and the quantum confinement in the energy band gap of the surface states. A large out-of-plane spin component also appears. The surface states penetrate inside the film to within approximately a few bilayers near the Brillouin-zone center, whereas they reach the center of the film near the Brillouinzone boundary.

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Origin of the surface-state band-splitting in ultrathin Bi films: from a Rashba effect to a parity effect

Cited by 69 publications

References 24 publications

Spin relaxation and the Elliott-Yafet parameter in W(001) ultrathin films: Surface states, anisotropy, and oscillation effects

Spin relaxation and the Elliott-Yafet parameter in W(001) ultrathin films: Surface states, anisotropy, and oscillation effects

Mixed Effects of the Atomic Arrangement and Surface Chemistry on the Electrodeposition of Bi Thin Films on n-GaAs Substrates

Tight-binding theory of surface spin states on bismuth thin films

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