Low-energy electron reflection from Au-passivated Ir(0 0 1) for application in imaging spin-filters

Vasilyev, Dmitry; Tusche, Christian; Giebels, F.; Gollisch, H.; Feder, R.; Kirschner, J.

doi:10.1016/j.elspec.2014.12.006

Cited by 36 publications

(46 citation statements)

References 19 publications

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“…E.g. for the Ir(001)-Au(1x1) spinfilter a reversal from -65% to +57% is facilitated by changing scattering energy from 10.25 to 11.5 eV [21]. A hemispherical analyzer can image a certain kinetic energy (E) interval (typically 10% of the pass energy) and polar emission angle ( ) range (up to +/-15°) to the exit field.…”

Section: Space and Spin: Multichannel Spin Detectionmentioning

confidence: 99%

“…The multichannel concept is based on the idea of preserving a two-dimensional electron distribution in the spin-polarized low-energy electron diffraction process. Recent developments towards multichannel spin detection in combination with a hemispherical analyzer [18] and with an emission electron microscope [20][21][22][23] exploit k ॥ -conservation in low-energy electron diffraction, similar to an optical mirror, as illustrated in Fig. 7 for real and reciprocal space.…”

Section: Space and Spin: Multichannel Spin Detectionmentioning

confidence: 99%

“…In the Halle-type of momentum microscope with dispersive energy filter this type of spin-filtering electron mirror presently yields 5 . 10 3 (k x ,k y ) data points in parallel [21][22][23]. In this instrument, sequential acquisition of k ॥ -distributions at many energies yields the complete spin-resolved valence band structure.…”

Section: Space and Spin: Multichannel Spin Detectionmentioning

confidence: 99%

“…A higher degree of parallelization can be reached by implementing a 2D imaging spin filter into the column of an electron microscope as demonstrated both for real-space imaging [20] and imaging of the reciprocal space in a momentum microscope [21][22][23]. This achievement is the result of intense development at the Max-Planck Institute (MPI) for Microstructure Physics in Halle, Germany.…”

Section: Introductionmentioning

confidence: 98%

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Space-, time- and spin-resolved photoemission

Schoenhense

Medjanik

Elmers

2015

Journal of Electron Spectroscopy and Related Phenomena

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This article reviews photoemission experiments that simultaneously resolve at least two of the following degrees of freedom: space (real and momentum space), time (intrinsic time scale of a fast experiment or time-of-flight) and spin. In the spatiotemporal domain, imaging of fast processes by PEEM gives direct insight into plasmon dynamics or magnetization processes. In the category real space & spin the novel concept of imaging spin filters is discussed. In the time & spin chapter we address time-of-flight spin detectors and ultrafast spin processes that are accessible by pump-and-probe techniques. A main part of the paper is devoted to the resolution of momentum-space & time. This is implemented in form of the time-of-flight momentum microscope, a very recent development of which the first instrument has been in operation since 2014. In an extended outlook chapter, the potential of new developments and of a novel, highly parallelized delay-line type electron detector will be discussed. The combination of all three degrees of freedom k-space, time & spin is emerging through the combination of the ToF momentum microscope with imaging spin filter. Outline

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Section: Space and Spin: Multichannel Spin Detectionmentioning

confidence: 99%

Section: Space and Spin: Multichannel Spin Detectionmentioning

confidence: 99%

Section: Space and Spin: Multichannel Spin Detectionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

See 2 more Smart Citations

Space-, time- and spin-resolved photoemission

Schoenhense

Medjanik

Elmers

2015

Journal of Electron Spectroscopy and Related Phenomena

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“…After reaching the base pressure and shortly before starting a measurement, a high-power flash (1500-1600 K, 235 W) for 10 s desorbs the remaining oxygen (see also Refs. [24][25][26]). …”

Section: Substrate and Spin Filter Preparationmentioning

confidence: 99%

Vectorial spin polarization detection in multichannel spin-resolved photoemission spectroscopy using an Ir(001) imaging spin filter

et al. 2017

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We report on spin-and angular-resolved photoemission spectroscopy using a high-resolution imaging spin filter based on a large Ir(001) crystal enhancing the effective figure of merit for spin detection by a factor of over 10 3 compared to standard single-channel detectors. Furthermore, we review the spin filter preparation and its lifetime. The spin filter efficiency is mapped on a broad range of scattering energies and azimuthal angles. Large spin filter efficiencies are observed for the spin component perpendicular as well as parallel to the scattering plane depending on the azimuthal orientation of the spin filter crystal. A spin rotator capable of manipulating the spin direction prior to detection complements the measurement of three observables, thus allowing for a derivation of all three components of the spin polarization vector in multichannel spin polarimetry. The experimental results nicely agree with spin-polarized low-energy electron diffraction calculations based on a fully relativistic multiple scattering method in the framework of spin-polarized density functional theory.

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Giant Rashba‐Type Spin Splitting in Ferroelectric GeTe(111)

et al. 2015

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A comprehensive mapping of the spin polarization of the electronic bands in ferroelectric α-GeTe(111) films has been performed using a time-of-flight momentum microscope equipped with an imaging spin filter that enables a simultaneous measurement of more than 10.000 data points (voxels). A Rashba type splitting of both surface and bulk bands with opposite spin helicity of the inner and outer Rashba bands is found revealing a complex spin texture at the Fermi energy. The switchable inner electric field of GeTe implies new functionalities for spintronic devices. The strong coupling of electron momentum and spin in low-dimensional structures allows an electrically controlled spin manipulation in spintronic devices [1-4], e.g. via the Rashba effect [5]. The Rashba effect has first been experimentally demonstrated in semiconductor heterostructures, where an electrical field perpendicular to the layered structure, i.e. perpendicular to the electron momentum, determines the electron spin orientation relative to its momentum [6-8]. An asymmetric interface structure causes the necessary inversion symmetry breaking and accounts for the special spin-splitting of electron states, the Rashba effect [5], the size of which can be tuned by the strength of the electrical field. For most semiconducting materials the Rashba effect causes only a quite small splitting of the order of 10 −2 ˚ A −1 and thus requires experiments at very low temperatures [9-11] and also implies large lateral dimensions for potential spintronic applications. A considerably larger splitting has been predicted theoretically [12] and was recently found experimentally for the surface states of GeTe(111) [13, 14]. GeTe is a ferroelectric semiconductor with a Curie temperature of 700 K. Thus, besides the interface induced Rashba splitting, the ferroelectric properties also imply a broken inversion symmetry within the bulk and thus would allow for the electrical tuning of the bulk Rashba splitting via switching the ferroelectric polarization [12, 15, 16]. This effect is of great interest for non-volatile spin orbitronics [10]. For GeTe a bulk Rashba splitting of 0.19Å19Å −1 has been predicted theoretically [12]. Experimentally, bulk-Rashba bands are rare and have only been found in the layered polar semiconductors BiTeCl and BiTeI [17-20] that, however, are not switchable. A characterization of the ferroelectric properties and a measurement of the spin polarization of the surface states of GeTe(111) at selected k-points has been performed previously by force microscopy [21, 22] and spin-resolved angular resolved photoemission spectroscopy, respectively [13]. A recent experimental and theoretical study revealed that at the Fermi level the hybridization of surface and bulk states causes surface-bulk resonant states resulting in unconventional spin topologies with chiral symmetry [14]. Here, we demonstrate the spin structure of surface and bulk bands of the GeTe(111) surface using the novel pho-toemission technique of spin-resolved time-of-flight momentum microsco...

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Low-energy electron reflection from Au-passivated Ir(0 0 1) for application in imaging spin-filters

Cited by 36 publications

References 19 publications

Space-, time- and spin-resolved photoemission

Space-, time- and spin-resolved photoemission

Vectorial spin polarization detection in multichannel spin-resolved photoemission spectroscopy using an Ir(001) imaging spin filter

Giant Rashba‐Type Spin Splitting in Ferroelectric GeTe(111)

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