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Pincelli T, Petrov VN, Brajnik G, Ciprian R, Lollobrigida V, Torelli P, Krizmancic D, Salvador F, De Luisa A, Sergo R, Gubertini A, Cautero G, Carrato S, Rossi G, Panaccione G. Design and optimization of a modular setup for measurements of three-dimensional spin polarization with ultrafast pulsed sources. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:035111. [PMID: 27036823 DOI: 10.1063/1.4943255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
ULTRASPIN is an apparatus devoted to the measurement of the spin polarization (SP) of electrons ejected from solid surfaces in a UHV environment. It is designed to exploit ultrafast light sources (free electron laser or laser high harmonic generation) and to perform (photo)electron spin analysis by an arrangement of Mott scattering polarimeters that measure the full SP vector. The system consists of two interconnected UHV vessels: one for surface science sample cleaning treatments, e-beam deposition of ultrathin films, and low energy electron diffraction/AES characterization. The sample environment in the polarimeter allows for cryogenic cooling and in-operando application of electric and magnetic fields. The photoelectrons are collected by an electrostatic accelerator and transport lens that form a periaxial beam that is subsequently directed by a Y-shaped electrostatic deflector to either one of the two orthogonal Mott polarimeters. The apparatus has been designed to operate in the extreme conditions of ultraintense single-X-ray pulses as originated by free electron lasers (up to 1 kHz), but it allows also for the single electron counting mode suitable when using statistical sources such as synchrotron radiation, cw-laser, or e-gun beams (up to 150 kcps).
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Affiliation(s)
- T Pincelli
- Dipartimento di Fisica, Università degli studi di Milano, Via Celoria 16, 20133 Milano, Italy
| | - V N Petrov
- Saint Petersburg State Polytechnical University, Politechnicheskaya Street 29, 195251 Saint Petersburg, Russia
| | - G Brajnik
- Università degli Studi di Trieste, Piazzale Europa 1, 34127 Trieste, Italy
| | - R Ciprian
- Laboratorio TASC, IOM-CNR, S.S. 14 km 163.5, Basovizza, 34149 Trieste, Italy
| | - V Lollobrigida
- Dipartimento di Matematica e Fisica, Università Roma Tre, I-00146 Rome, Italy
| | - P Torelli
- Laboratorio TASC, IOM-CNR, S.S. 14 km 163.5, Basovizza, 34149 Trieste, Italy
| | - D Krizmancic
- Laboratorio TASC, IOM-CNR, S.S. 14 km 163.5, Basovizza, 34149 Trieste, Italy
| | - F Salvador
- Laboratorio TASC, IOM-CNR, S.S. 14 km 163.5, Basovizza, 34149 Trieste, Italy
| | - A De Luisa
- Laboratorio TASC, IOM-CNR, S.S. 14 km 163.5, Basovizza, 34149 Trieste, Italy
| | - R Sergo
- Sincrotrone Trieste S.C.p.A, Strada Statale 14-km 163.5 in AREA Science Park, Basovizza, 34149 Trieste, Italy
| | - A Gubertini
- Sincrotrone Trieste S.C.p.A, Strada Statale 14-km 163.5 in AREA Science Park, Basovizza, 34149 Trieste, Italy
| | - G Cautero
- Sincrotrone Trieste S.C.p.A, Strada Statale 14-km 163.5 in AREA Science Park, Basovizza, 34149 Trieste, Italy
| | - S Carrato
- Università degli Studi di Trieste, Piazzale Europa 1, 34127 Trieste, Italy
| | - G Rossi
- Dipartimento di Fisica, Università degli studi di Milano, Via Celoria 16, 20133 Milano, Italy
| | - G Panaccione
- Laboratorio TASC, IOM-CNR, S.S. 14 km 163.5, Basovizza, 34149 Trieste, Italy
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Naaman R, Waldeck DH. Spintronics and chirality: spin selectivity in electron transport through chiral molecules. Annu Rev Phys Chem 2015; 66:263-81. [PMID: 25622190 DOI: 10.1146/annurev-physchem-040214-121554] [Citation(s) in RCA: 242] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Recent experiments have demonstrated that the electron transmission yield through chiral molecules depends on the electron spin orientation. This phenomenon has been termed the chiral-induced spin selectivity (CISS) effect, and it provides a challenge to theory and promise for organic molecule-based spintronic devices. This article reviews recent developments in our understanding of CISS. Different theoretical models have been used to describe the effect; however, they all presume an unusually large spin-orbit coupling in chiral molecules for the effect to display the magnitudes seen in experiments. A simplified model for an electron's transport through a chiral potential suggests that these large couplings can be manifested. Techniques for measuring spin-selective electron transport through molecules are overviewed, and some examples of recent experiments are described. Finally, we present results obtained by studying several systems, and we describe the possible application of the CISS effect for memory devices.
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Affiliation(s)
- Ron Naaman
- Department of Chemical Physics, Weizmann Institute, Rehovot 76100, Israel;
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Göhler B, Hamelbeck V, Markus TZ, Kettner M, Hanne GF, Vager Z, Naaman R, Zacharias H. Spin selectivity in electron transmission through self-assembled monolayers of double-stranded DNA. Science 2011; 331:894-7. [PMID: 21330541 DOI: 10.1126/science.1199339] [Citation(s) in RCA: 371] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
In electron-transfer processes, spin effects normally are seen either in magnetic materials or in systems containing heavy atoms that facilitate spin-orbit coupling. We report spin-selective transmission of electrons through self-assembled monolayers of double-stranded DNA on gold. By directly measuring the spin of the transmitted electrons with a Mott polarimeter, we found spin polarizations exceeding 60% at room temperature. The spin-polarized photoelectrons were observed even when the photoelectrons were generated with unpolarized light. The observed spin selectivity at room temperature was extremely high as compared with other known spin filters. The spin filtration efficiency depended on the length of the DNA in the monolayer and its organization.
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Affiliation(s)
- B Göhler
- Physikalisches Institut, Westfälische Wilhelms-Universität Münster, Münster, Germany
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Tioukine V, Aulenbacher K, Riehn E. A Mott polarimeter operating at MeV electron beam energies. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2011; 82:033303. [PMID: 21456728 DOI: 10.1063/1.3556593] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We have developed a Mott electron polarimeter for the Mainzer microtron (MAMI) accelerator in Mainz, Germany. At beam energies ranging between 1.0 and 3.5 MeV two double focusing magnet spectrometers collect elastically backscattered electrons from gold targets. In spite of the small spectrometer acceptance, a sufficient statistical efficiency is achieved to provide very fast measurements if beam currents typical for experiments at MAMI are being used. High reproducibility is achieved, demonstrating that the results of asymmetry measurements are independent of the primary beam current in a range from 0.004 to 45 μA at a level of <1% relative variation. Compared to low energy polarimeters of similar construction an improvement of a factor 2-3 in absolute accuracy seems possible.
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Affiliation(s)
- V Tioukine
- Institut für Kernphysik der Johannes Gutenberg-Universität Mainz D-55128 Mainz, Germany.
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Kozela A, Ban G, Białek A, Bodek K, Gorel P, Kirch K, Kistryn S, Kuźniak M, Naviliat-Cuncic O, Pulut J, Severijns N, Stephan E, Zejma J. Measurement of the transverse polarization of electrons emitted in free-neutron decay. PHYSICAL REVIEW LETTERS 2009; 102:172301. [PMID: 19518775 DOI: 10.1103/physrevlett.102.172301] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2009] [Indexed: 05/27/2023]
Abstract
Both components of the transverse polarization of electrons (sigmaT1, sigmaT2) emitted in the beta-decay of polarized, free neutrons have been measured. The T-odd, P-odd correlation coefficient quantifying sigmaT2, perpendicular to the neutron polarization and electron momentum, was found to be R=0.008+/-0.015+/-0.005. This value is consistent with time reversal invariance and significantly improves limits on the relative strength of imaginary scalar couplings in the weak interaction. The value obtained for the correlation coefficient associated with sigmaT1, N=0.056+/-0.011+/-0.005, agrees with the Standard Model expectation, providing an important sensitivity test of the experimental setup.
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Affiliation(s)
- A Kozela
- Henryk Niewodniczański Institute of Nuclear Physics PAN, Cracow, Poland
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