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Gotter R, Verna A, Sbroscia M, Moroni R, Bisio F, Iacobucci S, Offi F, Vaidya SR, Ruocco A, Stefani G. Unexpectedly Large Electron Correlation Measured in Auger Spectra of Ferromagnetic Iron Thin Films: Orbital-Selected Coulomb and Exchange Contributions. Phys Rev Lett 2020; 125:067202. [PMID: 32845695 DOI: 10.1103/physrevlett.125.067202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 07/08/2020] [Indexed: 06/11/2023]
Abstract
A set of electron-correlation energies as large as 10 eV have been measured for a magnetic 2 ML Fe film deposited on Ag(001). By exploiting the spin selectivity in angle-resolved Auger-photoelectron coincidence spectroscopy and the Cini-Sawatzky theory, the core-valence-valence Auger spectrum of a spin-polarized system have been resolved: correlation energies have been determined for each individual combination of the two holes created in the four subbands involved in the decay: majority and minority spin, as well as e_{g} and t_{2g}. The energy difference between final states with parallel and antiparallel spin of the two emitted electrons is ascribed to the spin-flip energy for the final ion state, thus disentangling the contributions of Coulomb and exchange interactions.
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Affiliation(s)
- R Gotter
- CNR-IOM, Istituto Officina dei Materiali, c/o Area Science Park, SS14 km 163,5 I-34149 Basovizza-Trieste, Italy
| | - A Verna
- Dipartimento di Scienze, Università degli Studi Roma Tre, Via della Vasca Navale 84, I-00146 Rome, Italy
| | - M Sbroscia
- Dipartimento di Scienze, Università degli Studi Roma Tre, Via della Vasca Navale 84, I-00146 Rome, Italy
| | - R Moroni
- CNR-SPIN, Corso Perrone 24, I-16152 Genova, Italy
| | - F Bisio
- CNR-SPIN, Corso Perrone 24, I-16152 Genova, Italy
| | - S Iacobucci
- Dipartimento di Scienze, Università degli Studi Roma Tre, Via della Vasca Navale 84, I-00146 Rome, Italy
- CNR-ISM, Via Fosso del Cavaliere 100, 00133 Roma, Italy
| | - F Offi
- Dipartimento di Scienze, Università degli Studi Roma Tre, Via della Vasca Navale 84, I-00146 Rome, Italy
| | - S R Vaidya
- CNR-IOM, Istituto Officina dei Materiali, c/o Area Science Park, SS14 km 163,5 I-34149 Basovizza-Trieste, Italy
- Scuola di Dottorato in Nanotecnologie, Università di Trieste, Piazzale Europa 1, I-34127 Trieste, Italy
| | - A Ruocco
- Dipartimento di Scienze, Università degli Studi Roma Tre, Via della Vasca Navale 84, I-00146 Rome, Italy
| | - G Stefani
- Dipartimento di Scienze, Università degli Studi Roma Tre, Via della Vasca Navale 84, I-00146 Rome, Italy
- CNR-ISM, Via Fosso del Cavaliere 100, 00133 Roma, Italy
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Zhang KHL, Egdell RG, Offi F, Iacobucci S, Petaccia L, Gorovikov S, King PDC. Microscopic origin of electron accumulation in In2O3. Phys Rev Lett 2013; 110:056803. [PMID: 23414041 DOI: 10.1103/physrevlett.110.056803] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Indexed: 06/01/2023]
Abstract
Angle-resolved photoemission spectroscopy reveals the presence of a two-dimensional electron gas at the surface of In(2)O(3)(111). Quantized subband states arise within a confining potential well associated with surface electron accumulation. Coupled Poisson-Schrödinger calculations suggest that downward band bending for the conduction band must be much bigger than band bending in the valence band. Surface oxygen vacancies acting as doubly ionized shallow donors are shown to provide the free electrons within this accumulation layer. Identification of the origin of electron accumulation in transparent conducting oxides has significant implications in the realization of devices based on these compounds.
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Affiliation(s)
- K H L Zhang
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford OX1 3QR, United Kingdom
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Offi F, Iacobucci S, Petaccia L, Gorovikov S, Vilmercati P, Rizzo A, Ruocco A, Goldoni A, Stefani G, Panaccione G. The attenuation length of low energy electrons in Yb. J Phys Condens Matter 2010; 22:305002. [PMID: 21399353 DOI: 10.1088/0953-8984/22/30/305002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Photoelectron emission spectra in a photon energy range between 7.5 and 21 eV are measured for in situ grown polycrystalline Yb films. By comparing bulk and surface core level shifted 4f components we give an estimation of the effective attenuation length (EAL) for low energy (6-20 eV) electrons in Yb, establishing a moderate increase of the EAL upon electron energy decrease. The experimental EAL data are found to be a factor of four smaller than those predicted from the so-called 'universal curve'.
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Affiliation(s)
- F Offi
- CNISM and Dipartimento di Fisica, Università Roma Tre, Rome, Italy.
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Abstract
An efficient synthesis of tri-, tetra-, and pentasaccharide cyclic phosphates 1-5, structurally related to natural inositol phosphate glycans, is reported. The title compounds were assembled by PhSeOTf-promoted glycosylation of the known glucosamine precursor, t-butyldimethylsilyl 2-azido-3,6-di-O-benzyl-2-deoxy-beta-D-glucopyranoside (8) with protected 1-methylthio mono-, di-, and trimannosides 7a-c, and, after conversion into glycosyl fluorides, Cp2ZrCl2- AgOTf-promoted glycosylation of differentially protected optically pure 1D-myo-inositol 11. The syntheses were completed by installing the cyclic phosphate moieties with methylpyridinium dichlorophosphate and finally, removal of all protecting groups by dissolving-metal reduction.
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Affiliation(s)
- C H Jaworek
- Department of Chemistry, Tufts University, Medford, MA 02155, USA
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Iacobucci S, Marassi L, Camilloni R, Nannarone S, Stefani G. Reflection (e,2e) spectroscopy on surfaces. Phys Rev B Condens Matter 1995; 51:10252-10255. [PMID: 9977717 DOI: 10.1103/physrevb.51.10252] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Curró G, Cosso R, Sancrotti M, Duó L, D'Addato S, Nannarone S, Iacobucci S, Panaccione G, Weightman P. Synchrotron-radiation investigation of the chemical dependence of the vacancy-satellite structure of the Ni L3VV spectra in Ni silicides. Phys Rev B Condens Matter 1992; 46:15652-15659. [PMID: 10003705 DOI: 10.1103/physrevb.46.15652] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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