Large enhancement of spin polarization observed by photoelectrons from a strained GaAs layer

Nakanishi, Toru; Aoyagi, H.; Horinaka, Hiromichi; Kamiya, Yuichi; Kato, Toshihiro; Nakamura, S.; Saka, Takashi; Tsubata, M.

doi:10.1016/0375-9601(91)90995-k

Cited by 133 publications

(28 citation statements)

References 8 publications

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“…Highly-polarized electrons are obtained from GaAs by directing a circularly-polarized laser beam on to a thin (typically 100 nm) p-doped epilayer of strained GaAs [203], of strained InGaAs [204], and of a short period superlattice [205]. Only a small fraction of the photons are absorbed in the epilayer.…”

Section: Polarized Electronsmentioning

confidence: 99%

Revealing Fundamental Interactions: the Role of Polarized Positrons and Electrons at the Linear Collider

Moortgat‐Pick¹,

U.²,

Abe³

et al. 2005

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Section: Polarized Electronsmentioning

confidence: 99%

Revealing Fundamental Interactions: the Role of Polarized Positrons and Electrons at the Linear Collider

Moortgat‐Pick¹,

U.²,

Abe³

et al. 2005

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“…50 The structure of the photocathode, manufactured at the ANU, 51 is similar to that described previously 52 where values of up to 80% electron spin polarization were achieved. In the present case, however, only ͑50± 4͒% spin polarization is achieved at a laser wavelength of 850 nm.…”

Section: The Anu "E 2e… Spectrometermentioning

confidence: 85%

Invited Article: An improved double-toroidal spectrometer for gas phase (e,2e) studies

Lower

Panajotović

Bellm

et al. 2007

Review of Scientific Instruments

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A new spectrometer is described for measuring the momentum distributions of scattered electrons arising from electron-atom and electron-molecule ionization experiments. It incorporates and builds on elements from a number of previous designs, namely, a source of polarized electrons and two high-efficiency electrostatic electron energy analyzers. The analyzers each comprise a seven-element retarding-electrostatic lens system, four toroidal-sector electrodes, and a fast position-and-time-sensitive two-dimensional delay-line detector. Results are presented for the electron-impact-induced ionization of helium and the elastic scattering of electrons from argon and helium which demonstrate that high levels of momentum resolution and data-collection efficiency are achieved. Problematic aspects regarding variations in collection efficiency over the accepted momentum phase space are addressed and a methodology for their correction presented. Principles behind the present design and previous designs for electrostatic analyzers based around electrodes of toroidal-sector geometry are discussed and a framework is provided for optimizing future devices.

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“…In particular, optical methods, also known as optical spin orientation, use polarized-light irradiation. For example, electrons in the valence band of strained and surface-treated GaAs can be excited by circularly polarized light and emitted with ∼ 80 % spin polarization [4]. GaAs photocathodes are widely used as spin-polarized electron source in lowenergy electron microscopy [5], in accelerators used in high-energy physics [6], etc.…”

mentioning

confidence: 99%

Spin-conserving and reversing photoemission from the surface states ofBi2Se3and Au (111)

Ryoo

Park

2016

Phys. Rev. B

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We present a theory based on first-principles calculations explaining (i) why the tunability of spin polarizations of photoelectrons from Bi2Se3 (111) depends on the band index and Bloch wavevector of the surface state and (ii) why such tunability is absent in the case of isosymmetric Au (111). The results provide not only an explanation for the recent, puzzling experimental observations but also a guide toward making highly-tunable spin-polarized electron sources from topological insulators.Since the beginning of spintronics, constant efforts have been made to generate electrons with a high degree of spin polarization using transport [1], optical [2], and magnetic resonance methods [3]. In particular, optical methods, also known as optical spin orientation, use polarized-light irradiation. For example, electrons in the valence band of strained and surface-treated GaAs can be excited by circularly polarized light and emitted with ∼ 80 % spin polarization [4]. GaAs photocathodes are widely used as spin-polarized electron source in lowenergy electron microscopy [5], in accelerators used in high-energy physics [6], etc.Recently, it has been proposed that topological insulators can serve as a spin-polarized electron source when irradiated with polarized light [7]. By changing the polarization of light and the direction toward which photoelectrons are collected, one can obtain an electron beam which is spin-polarized in an arbitrary direction, with a 100 % degree of spin polarization [8] (the measured degree is over 80 % [9]). On the other hand, the direction of spin polarization of electrons generated from a strainedGaAs photocathode is fixed by the surface-normal direction perpendicular to which the strain is applied. Moreover, unlike GaAs photocathodes, in which the photon energy is fixed to ∼ 1.5 eV by the material band gap, photocathodes using a topological insulator can be operated within a wide range of photon energies. Even if there could be several technological hurdles that should be overcome, topological insulators are conceptually new candidates for photocathodes for spintronics.Despite these recent developments, we still do not understand the results from some of the key spin-and angleresolved photoemission spectroscopy (SARPES) experi-

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Large enhancement of spin polarization observed by photoelectrons from a strained GaAs layer

Cited by 133 publications

References 8 publications

Revealing Fundamental Interactions: the Role of Polarized Positrons and Electrons at the Linear Collider

Revealing Fundamental Interactions: the Role of Polarized Positrons and Electrons at the Linear Collider

Invited Article: An improved double-toroidal spectrometer for gas phase (e,2e) studies

Spin-conserving and reversing photoemission from the surface states ofBi2Se3and Au (111)

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