Spectral detection of spin-polarized ultra low-energy electrons in semiconductor heterostructures

Golyashov, V. A.; Rusetsky, V.S.; Шамирзаев, Т. С.; Дмитриев, Д. В.; Kislykh, N. V.; Миронов, А. В.; Aksenov, V. I.; Tereshchenko, O. E.

doi:10.1016/j.ultramic.2020.113076

Cited by 11 publications

(21 citation statements)

References 19 publications

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“…Electrons, injected with out-of-plane polarization, recombine radiatively in the semiconductor structure with circular light polarization [clockwise (CW) or counterclockwise (CCW)], which can be detected by means of polarizing optics (quarter-wave plate and linear polarizer). The measured light polarization degree P CLz = (I + -I -)/ (I + + I -), where I + (I -) is the intensity of the + ( -) polarized emission component with AE helicity, is proportional to the polarization of injected electrons and thus allows the spin projection to be determined out-of-plane of the detector (Gö ckel et al, 1990;Alperovich et al, 2005;Golyashov et al, 2020). This circular polarization P CL is directly related to the electron polarization P e at the instant of recombination by P CL = P e , where P e = (N " À N # )/(N " + N # ), and N " and N # are the densities of electrons with 1/2 spin projection along the direction of light propagation.…”

Section: Detection Of Out-of-plane Spin Components Inmentioning

confidence: 99%

“…The coefficient is equal to À1/2 for a cubic bulk III-V semiconductor like GaAs with degenerate heavy-hole and light-hole valence bands. The circular polarization of the CL light reflects the spin-polarization P e = P 0 of the recombining electrons, where is the depolarization factor studied in detail as a function of injected electron energy from spectral CL measurements (Golyashov et al, 2020). An asymmetry measured in the optical experiment for known electron beam polarization A = P CL /P 0 = = S is the Sherman function for optical detection of the incident electron polarization.…”

Section: Detection Of Out-of-plane Spin Components Inmentioning

confidence: 99%

“…The intensity rapidly increases by several orders of magnitude starting from 0.5 eV to 1 eV, caused by electron injection into the semiconductor bulk and their subsequent radiative recombination. The absence of the signal at lower voltages is associated with the fact that the injected electron energy is insufficient to overcome the surface barrier and enter the Al x Ga 1Àx As conduction band (Golyashov et al, 2020). As a result, the majority of the electrons are reflected from the barrier and nonradiatively recombine at the anode surface.…”

Section: Detection Of Spin Polarization In Image-type Modementioning

confidence: 99%

“…) is proportional to the polarization of injected electrons and thus allows the user to determine two spin projections in the plane of the detector. The CL method allows the user to measure all three spin components: two in-plane components using the spin-filter effect in an FM film with in-plane easy axes (Li et al, 2014) and the third (perpendicular to target surface) by measuring CL polarization light from recombined polarized electrons with holes in the semiconductor (Gö ckel et al, 1990;Alperovich et al, 2005;Golyashov et al, 2020).…”

mentioning

confidence: 99%

“…We developed an image-type spin detector prototype for measuring the normal (to the surface of the detector) component of the electron beam polarization, utilizing the injection of spin-polarized free electrons in a heterostructure with quantum wells (QWs) and recording the circularly polarized CL with spatial resolution. A flat vacuum photodiode composed of two effective NEA semiconductor electrodes was designed and studied (Rodionov et al, 2017;Tereshchenko et al, 2017;Golyashov et al, 2020). Schematic presentation of the compact vacuum photodiode with photographs of the device from the photocathode side and the target (anode) and operation principle for the investigation of spin-dependent injection are shown in Figs.…”

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confidence: 99%

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A new imaging concept in spin polarimetry based on the spin-filter effect

Tereshchenko¹,

Golyashov²,

Rusetsky³

et al. 2021

J Synchrotron Rad

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The concept of an imaging-type 3D spin detector, based on the combination of spin-exchange interactions in the ferromagnetic (FM) film and spin selectivity of the electron–photon conversion effect in a semiconductor heterostructure, is proposed and demonstrated on a model system. This novel multichannel concept is based on the idea of direct transfer of a 2D spin-polarized electron distribution to image cathodoluminescence (CL). The detector is a hybrid structure consisting of a thin magnetic layer deposited on a semiconductor structure allowing measurement of the spatial and polarization-dependent CL intensity from injected spin-polarized free electrons. The idea is to use spin-dependent electron transmission through in-plane magnetized FM film for in-plane spin detection by measuring the CL intensity from recombined electrons transmitted in the semiconductor. For the incoming electrons with out-of-plane spin polarization, the intensity of circularly polarized CL light can be detected from recombined polarized electrons with holes in the semiconductor. In order to demonstrate the ability of the solid-state spin detector in the image-type mode operation, a spin detector prototype was developed, which consists of a compact proximity focused vacuum tube with a spin-polarized electron source [p-GaAs(Cs,O)], a negative electron affinity (NEA) photocathode and the target [semiconductor heterostructure with quantum wells also with NEA]. The injection of polarized low-energy electrons into the target by varying the kinetic energy in the range 0.5–3.0 eV and up to 1.3 keV was studied in image-type mode. The figure of merit as a function of electron kinetic energy and the target temperature is determined. The spin asymmetry of the CL intensity in a ferromagnetic/semiconductor (FM-SC) junction provides a compact optical method for measuring spin polarization of free-electron beams in image-type mode. The FM-SC detector has the potential for realizing multichannel 3D vectorial reconstruction of spin polarization in momentum microscope and angle-resolved photoelectron spectroscopy systems.

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Section: Detection Of Out-of-plane Spin Components Inmentioning

confidence: 99%

Section: Detection Of Out-of-plane Spin Components Inmentioning

confidence: 99%

Section: Detection Of Spin Polarization In Image-type Modementioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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A new imaging concept in spin polarimetry based on the spin-filter effect

Tereshchenko¹,

Golyashov²,

Rusetsky³

et al. 2021

J Synchrotron Rad

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Insights into performance enhancement mechanism of GaAs(100) photocathode by Cs/Li/O and Cs/Li/NF3 co-deposition

Zhang,

Zhang

et al. 2024

Surfaces and Interfaces

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Electron-driven processes in enantiomeric forms of glutamic acid initiated by low-energy resonance electron attachment

Pshenichnyuk,

Asfandiarov,

Rakhmeyev

et al. 2024

The Journal of Chemical Physics

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Low-energy (0–14 eV) resonance electron interaction and fragment species produced by dissociative electron attachment (DEA) for enantiomeric forms of glutamic acid (Glu) are studied under gas-phase conditions by means of DEA spectroscopy and density functional theory calculations. Contrary to a series of amino acids studied earlier employing the DEA technique, the most abundant species are not associated with the elimination of a hydrogen atom from the parent molecular negative ion. Besides this less intense closed-shell [Glu – H]– fragment, only two mass-selected negative ions, [Glu – 19]– and [Glu – 76]–, are detected within the same electron energy region, with the yield maximum observed at around 0.9 eV. This value matches well the energy of vertical electron attachment into the lowest normally empty π* COOH molecular orbital of Glu located at 0.88 eV according to the present B3LYP/6-31G(d) calculations. Although the detection of asymmetric DEA properties a priori is not accessible under the present experimental conditions, “chirality non-conservation” can be associated with some decay channels. Evidently, the measured spectra for the L- and D-forms are found to be identical, the results, nevertheless, being of interest for the forthcoming experiments utilizing spin-polarized electron beam as a chiral factor in the framework of conventional DEA technique.

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Spectral detection of spin-polarized ultra low-energy electrons in semiconductor heterostructures

Cited by 11 publications

References 19 publications

A new imaging concept in spin polarimetry based on the spin-filter effect

A new imaging concept in spin polarimetry based on the spin-filter effect

Insights into performance enhancement mechanism of GaAs(100) photocathode by Cs/Li/O and Cs/Li/NF3 co-deposition

Electron-driven processes in enantiomeric forms of glutamic acid initiated by low-energy resonance electron attachment

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