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Sinclair J, Flores M, Brugh AM, Rajh T, Juelsholt M, Riaz AA, Schlueter C, Regoutz A, Birkel CS. In-Depth Analysis of the Species and Transformations during Sol Gel-Assisted V 2PC Synthesis. Inorg Chem 2024. [PMID: 38787450 DOI: 10.1021/acs.inorgchem.4c01160] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
The sol-gel reaction mechanism of 211 MAX phases has proven to be very complex when identifying the intermediate species, chemical processes, and conversions that occur from a mixture of metal salts and gelling agent into a crystalline ternary carbide. With mostly qualitative results in the literature (Cr2GaC, Cr2GeC, and V2GeC), additional analytical techniques, including thermal analysis, powder diffraction, total scattering, and various spectroscopic methods, are necessary to unravel the identity of the chemical compounds and transformations during the reaction. Here, we demonstrate the combination of these techniques to understand the details of the sol-gel synthesis of MAX phase V2PC. The metal phosphate complexes, as well as amorphous/nanocrystalline vanadium phosphate species (V in different oxidation states), are identified at all stages of the reaction and a full schematic of the reaction process is suggested. The early amorphous vanadium species undergo multiple changes of oxidation states while organic species decompose releasing a variety of small molecule gases. Amorphous oxides, analogous to [NH4][VO2][HPO4], V2PO4O, and VO2P2O7 are identified in the dried gel obtained during the early stages of the heating process (300 and 600 °C), respectively. They are carbothermally reduced starting at 900 °C and subsequently react to crystalline V2PC with the excess carbon in the reaction mixture. Through CHN analysis, we obtain an estimate of left-over amorphous carbon in the product which will guide future efforts of minimizing the amount of carbon in sol gel-produced MAX phases which is important for subsequent property studies.
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Affiliation(s)
- Jordan Sinclair
- School of Molecular Sciences, Arizona State University, Tempe AZ-85282, United States
| | - Marco Flores
- School of Molecular Sciences, Arizona State University, Tempe AZ-85282, United States
| | - Alexander M Brugh
- School of Molecular Sciences, Arizona State University, Tempe AZ-85282, United States
| | - Tijana Rajh
- School of Molecular Sciences, Arizona State University, Tempe AZ-85282, United States
| | - Mikkel Juelsholt
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom
| | - Aysha A Riaz
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | | | - Anna Regoutz
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Christina S Birkel
- School of Molecular Sciences, Arizona State University, Tempe AZ-85282, United States
- Department of Chemistry and Biochemistry, Technische Universität Darmstadt, 64283 Darmstadt, Germany
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2
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Ojha SK, Hazra S, Bera S, Gogoi SK, Mandal P, Maity J, Gloskovskii A, Schlueter C, Karmakar S, Jain M, Banerjee S, Gopalan V, Middey S. Quantum fluctuations lead to glassy electron dynamics in the good metal regime of electron doped KTaO 3. Nat Commun 2024; 15:3830. [PMID: 38714672 PMCID: PMC11076559 DOI: 10.1038/s41467-024-47956-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Accepted: 04/15/2024] [Indexed: 05/10/2024] Open
Abstract
One of the central challenges in condensed matter physics is to comprehend systems that have strong disorder and strong interactions. In the strongly localized regime, their subtle competition leads to glassy electron dynamics which ceases to exist well before the insulator-to-metal transition is approached as a function of doping. Here, we report on the discovery of glassy electron dynamics deep inside the good metal regime of an electron-doped quantum paraelectric system: KTaO3. We reveal that upon excitation of electrons from defect states to the conduction band, the excess injected carriers in the conduction band relax in a stretched exponential manner with a large relaxation time, and the system evinces simple aging phenomena-a telltale sign of glassy dynamics. Most significantly, we observe a critical slowing down of carrier dynamics below 35 K, concomitant with the onset of quantum paraelectricity in the undoped KTaO3. Our combined investigation using second harmonic generation technique, density functional theory and phenomenological modeling demonstrates quantum fluctuation-stabilized soft polar modes as the impetus for the glassy behavior. This study addresses one of the most fundamental questions regarding the potential promotion of glassiness by quantum fluctuations and opens a route for exploring glassy dynamics of electrons in a well-delocalized regime.
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Affiliation(s)
- Shashank Kumar Ojha
- Department of Physics, Indian Institute of Science, Bengaluru, 560012, India.
| | - Sankalpa Hazra
- Department of Physics, Indian Institute of Science, Bengaluru, 560012, India
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Surajit Bera
- Department of Physics, Indian Institute of Science, Bengaluru, 560012, India
| | - Sanat Kumar Gogoi
- Department of Physics, Indian Institute of Science, Bengaluru, 560012, India
- Department of Physics, Digboi College, Digboi, 786171, India
| | - Prithwijit Mandal
- Department of Physics, Indian Institute of Science, Bengaluru, 560012, India
| | - Jyotirmay Maity
- Department of Physics, Indian Institute of Science, Bengaluru, 560012, India
| | | | | | - Smarajit Karmakar
- Tata Institute of Fundamental Research, 36/P, Gopanpally Village, Serilingampally Mandal, Ranga Reddy District, Hyderabad, 500107, India
| | - Manish Jain
- Department of Physics, Indian Institute of Science, Bengaluru, 560012, India
| | - Sumilan Banerjee
- Department of Physics, Indian Institute of Science, Bengaluru, 560012, India.
| | - Venkatraman Gopalan
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Srimanta Middey
- Department of Physics, Indian Institute of Science, Bengaluru, 560012, India.
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3
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Büchner C, Kubitza N, Malik AM, Jamboretz J, Riaz AA, Zhu Y, Schlueter C, McCartney MR, Smith DJ, Regoutz A, Rohrer J, Birkel CS. Chemical Conversions within the Mo-Ga-C System: Layered Solids with Variable Ga Content. Inorg Chem 2024; 63:7725-7734. [PMID: 38623051 DOI: 10.1021/acs.inorgchem.4c00107] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2024]
Abstract
Layered carbides are fascinating compounds due to their enormous structural and chemical diversity, as well as their potential to possess useful and tunable functional properties. Their preparation, however, is challenging and forces synthesis scientists to develop creative and innovative strategies to access high-quality materials. One unique compound among carbides is Mo2Ga2C. Its structure is related to the large and steadily growing family of 211 MAX phases that crystallize in a hexagonal structure (space group P63/mmc) with alternating layers of edge-sharing M6X octahedra and layers of the A-element. Mo2Ga2C also crystallizes in the same space group, with the difference that the A-element layer is occupied by two A-elements, here Ga, that sit right on top of each other (hence named "221" compound). Here, we propose that the Ga content in this compound is variable between 2:2, 2:1, and 2: ≤1 (and 2:0) Mo/Ga ratios. We demonstrate that one Ga layer can be selectively removed from Mo2Ga2C without jeopardizing the hexagonal P63/mmc structure. This is realized by chemical treatment of the 221 phase Mo2Ga2C with a Lewis acid, leading to the "conventional" 211 MAX phase Mo2GaC. Upon further reaction with CuCl2, more Ga is removed and replaced with Cu (instead of fully exfoliating into the Ga-free Mo2CTx MXene), leading to Mo2Ga1-xCuxC still crystallizing with space group P63/mmc, however, with a significantly larger c-lattice parameter. Furthermore, 211 Mo2GaC can be reacted with Ga to recover the initial 221 Mo2Ga2C. All three reaction pathways have not been reported previously and are supported by powder X-ray diffraction (PXRD), electron microscopy, X-ray spectroscopy, and density functional theory (DFT) calculations.
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Affiliation(s)
- Carina Büchner
- Department of Chemistry and Biochemistry, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Niels Kubitza
- Department of Chemistry and Biochemistry, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Ali M Malik
- Institute of Materials Science, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - John Jamboretz
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85281, United States
| | - Aysha A Riaz
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Yujiang Zhu
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | | | - Martha R McCartney
- Department of Physics, Arizona State University, Tempe, Arizona 85281, United States
| | - David J Smith
- Department of Physics, Arizona State University, Tempe, Arizona 85281, United States
| | - Anna Regoutz
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Jochen Rohrer
- Institute of Materials Science, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Christina S Birkel
- Department of Chemistry and Biochemistry, Technische Universität Darmstadt, 64287 Darmstadt, Germany
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85281, United States
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4
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Bibi SB, El-Zohry AM, Davies B, Grigorev V, Goodwin CM, Lömker P, Holm A, Ali-Löytty H, Garcia-Martinez F, Schlueter C, Soldemo M, Koroidov S, Hansson T. Multi-spectroscopic study of electrochemically-formed oxide-derived gold electrodes. Phys Chem Chem Phys 2024; 26:2332-2340. [PMID: 38165839 DOI: 10.1039/d3cp04009g] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2024]
Abstract
Oxide-derived metals are produced by reducing an oxide precursor. These materials, including gold, have shown improved catalytic performance over many native metals. The origin of this improvement for gold is not yet understood. In this study, operando non-resonant sum frequency generation (SFG) and ex situ high-pressure X-ray photoelectron spectroscopy (HP-XPS) have been employed to investigate electrochemically-formed oxide-derived gold (OD-Au) from polycrystalline gold surfaces. A range of different oxidizing conditions were used to form OD-Au in acidic aqueous medium (H3PO4, pH = 1). Our electrochemical data after OD-Au is generated suggest that the surface is metallic gold, however SFG signal variations indicate the presence of subsurface gold oxide remnants between the metallic gold surface layer and bulk gold. The HP-XPS results suggest that this subsurface gold oxide could be in the form of Au2O3 or Au(OH)3. Furthermore, the SFG measurements show that with reducing electrochemical treatments the original gold metallic state can be restored, meaning the subsurface gold oxide is released. This work demonstrates that remnants of gold oxide persist beneath the topmost gold layer when the OD-Au is created, potentially facilitating the understanding of the improved catalytic properties of OD-Au.
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Affiliation(s)
- Sara Boscolo Bibi
- Department of Physics, AlbaNova University Center, Stockholm University, 10691 Stockholm, Sweden.
| | - Ahmed M El-Zohry
- Department of Physics, AlbaNova University Center, Stockholm University, 10691 Stockholm, Sweden.
| | - Bernadette Davies
- Department of Physics, AlbaNova University Center, Stockholm University, 10691 Stockholm, Sweden.
- Department of Materials and Environmental Chemistry, Stockholm University, Svante Arrhenius väg 16C, 114 18 Stockholm, Sweden
| | - Vladimir Grigorev
- Department of Physics, AlbaNova University Center, Stockholm University, 10691 Stockholm, Sweden.
| | - Christopher M Goodwin
- Department of Physics, AlbaNova University Center, Stockholm University, 10691 Stockholm, Sweden.
| | - Patrick Lömker
- Department of Physics, AlbaNova University Center, Stockholm University, 10691 Stockholm, Sweden.
| | - Alexander Holm
- Department of Physics, AlbaNova University Center, Stockholm University, 10691 Stockholm, Sweden.
| | - Harri Ali-Löytty
- Surface Science Group, Photonics Laboratory, Tampere University, P.O. Box 692, FI-33014 Tampere University, Finland
| | | | - Christoph Schlueter
- Photon Science, Deutsches ElektronenSynchrotron (DESY), 22607 Hamburg, Germany
| | - Markus Soldemo
- Department of Physics, AlbaNova University Center, Stockholm University, 10691 Stockholm, Sweden.
| | - Sergey Koroidov
- Department of Physics, AlbaNova University Center, Stockholm University, 10691 Stockholm, Sweden.
| | - Tony Hansson
- Department of Physics, AlbaNova University Center, Stockholm University, 10691 Stockholm, Sweden.
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5
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Goodwin CM, Lömker P, Degerman D, Davies B, Shipilin M, Garcia-Martinez F, Koroidov S, Katja Mathiesen J, Rameshan R, Rodrigues GLS, Schlueter C, Amann P, Nilsson A. Operando probing of the surface chemistry during the Haber-Bosch process. Nature 2024; 625:282-286. [PMID: 38200297 PMCID: PMC10781625 DOI: 10.1038/s41586-023-06844-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 11/07/2023] [Indexed: 01/12/2024]
Abstract
The large-scale conversion of N2 and H2 into NH3 (refs. 1,2) over Fe and Ru catalysts3 for fertilizer production occurs through the Haber-Bosch process, which has been considered the most important scientific invention of the twentieth century4. The active component of the catalyst enabling the conversion was variously considered to be the oxide5, nitride2, metallic phase or surface nitride6, and the rate-limiting step has been associated with N2 dissociation7-9, reaction of the adsorbed nitrogen10 and also NH3 desorption11. This range of views reflects that the Haber-Bosch process operates at high temperatures and pressures, whereas surface-sensitive techniques that might differentiate between different mechanistic proposals require vacuum conditions. Mechanistic studies have accordingly long been limited to theoretical calculations12. Here we use X-ray photoelectron spectroscopy-capable of revealing the chemical state of catalytic surfaces and recently adapted to operando investigations13 of methanol14 and Fischer-Tropsch synthesis15-to determine the surface composition of Fe and Ru catalysts during NH3 production at pressures up to 1 bar and temperatures as high as 723 K. We find that, although flat and stepped Fe surfaces and Ru single-crystal surfaces all remain metallic, the latter are almost adsorbate free, whereas Fe catalysts retain a small amount of adsorbed N and develop at lower temperatures high amine (NHx) coverages on the stepped surfaces. These observations indicate that the rate-limiting step on Ru is always N2 dissociation. On Fe catalysts, by contrast and as predicted by theory16, hydrogenation of adsorbed N atoms is less efficient to the extent that the rate-limiting step switches following temperature lowering from N2 dissociation to the hydrogenation of surface species.
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Affiliation(s)
- Christopher M Goodwin
- Department of Physics, Stockholm University, AlbaNova University Center, Stockholm, Sweden.
- Materials Science, ALBA Synchrotron Light Facility, Cerdanyola del Vallés, Spain.
| | - Patrick Lömker
- Department of Physics, Stockholm University, AlbaNova University Center, Stockholm, Sweden
| | - David Degerman
- Department of Physics, Stockholm University, AlbaNova University Center, Stockholm, Sweden
| | - Bernadette Davies
- Department of Materials and Environmental Chemistry, Stockholm University, Stockholm, Sweden
| | - Mikhail Shipilin
- Department of Physics, Stockholm University, AlbaNova University Center, Stockholm, Sweden
| | | | - Sergey Koroidov
- Department of Physics, Stockholm University, AlbaNova University Center, Stockholm, Sweden
| | - Jette Katja Mathiesen
- Department of Physics, Stockholm University, AlbaNova University Center, Stockholm, Sweden
| | - Raffael Rameshan
- Institute of Physical Chemistry, Montan University Leoben, Leoben, Austria
| | - Gabriel L S Rodrigues
- Department of Physics, Stockholm University, AlbaNova University Center, Stockholm, Sweden
| | | | - Peter Amann
- Department of Physics, Stockholm University, AlbaNova University Center, Stockholm, Sweden
- Scienta Omicron AB, Uppsala, Sweden
| | - Anders Nilsson
- Department of Physics, Stockholm University, AlbaNova University Center, Stockholm, Sweden.
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6
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Mondal D, Mahapatra SR, Derrico AM, Rai RK, Paudel JR, Schlueter C, Gloskovskii A, Banerjee R, Hariki A, DeGroot FMF, Sarma DD, Narayan A, Nukala P, Gray AX, Aetukuri NPB. Modulation-doping a correlated electron insulator. Nat Commun 2023; 14:6210. [PMID: 37798279 PMCID: PMC10556139 DOI: 10.1038/s41467-023-41816-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 09/13/2023] [Indexed: 10/07/2023] Open
Abstract
Correlated electron materials (CEMs) host a rich variety of condensed matter phases. Vanadium dioxide (VO2) is a prototypical CEM with a temperature-dependent metal-to-insulator (MIT) transition with a concomitant crystal symmetry change. External control of MIT in VO2-especially without inducing structural changes-has been a long-standing challenge. In this work, we design and synthesize modulation-doped VO2-based thin film heterostructures that closely emulate a textbook example of filling control in a correlated electron insulator. Using a combination of charge transport, hard X-ray photoelectron spectroscopy, and structural characterization, we show that the insulating state can be doped to achieve carrier densities greater than 5 × 1021 cm-3 without inducing any measurable structural changes. We find that the MIT temperature (TMIT) continuously decreases with increasing carrier concentration. Remarkably, the insulating state is robust even at doping concentrations as high as ~0.2 e-/vanadium. Finally, our work reveals modulation-doping as a viable method for electronic control of phase transitions in correlated electron oxides with the potential for use in future devices based on electric-field controlled phase transitions.
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Affiliation(s)
- Debasish Mondal
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bengaluru, Karnataka, India
| | - Smruti Rekha Mahapatra
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bengaluru, Karnataka, India
| | | | - Rajeev Kumar Rai
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore, Karnataka, India
| | - Jay R Paudel
- Department of Physics, Temple University, Philadelphia, PA, USA
| | | | | | - Rajdeep Banerjee
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bengaluru, Karnataka, India
| | - Atsushi Hariki
- Department of Physics and Electronics, Graduate School of Engineering, Osaka Metropolitan University, Osaka, Japan
| | - Frank M F DeGroot
- Utrecht University, Inorganic Chemistry and Catalysis Group Universiteitsweg 99, Utrecht, The Netherlands
| | - D D Sarma
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bengaluru, Karnataka, India
| | - Awadhesh Narayan
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bengaluru, Karnataka, India
| | - Pavan Nukala
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore, Karnataka, India
| | - Alexander X Gray
- Department of Physics, Temple University, Philadelphia, PA, USA.
| | - Naga Phani B Aetukuri
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bengaluru, Karnataka, India.
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7
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Tkach O, Vo TP, Fedchenko O, Medjanik K, Lytvynenko Y, Babenkov S, Vasilyev D, Nguyen QL, Peixoto TRF, Gloskowskii A, Schlueter C, Chernov S, Hoesch M, Kutnyakhov D, Scholz M, Wenthaus L, Wind N, Marotzke S, Winkelmann A, Rossnagel K, Minár J, Elmers HJ, Schönhense G. Circular dichroism in hard X-ray photoelectron diffraction observed by time-of-flight momentum microscopy. Ultramicroscopy 2023; 250:113750. [PMID: 37178606 DOI: 10.1016/j.ultramic.2023.113750] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 04/01/2023] [Accepted: 05/04/2023] [Indexed: 05/15/2023]
Abstract
X-ray photoelectron diffraction (XPD) is a powerful technique that yields detailed structural information of solids and thin films that complements electronic structure measurements. Among the strongholds of XPD we can identify dopant sites, track structural phase transitions, and perform holographic reconstruction. High-resolution imaging of kll-distributions (momentum microscopy) presents a new approach to core-level photoemission. It yields full-field kx-ky XPD patterns with unprecedented acquisition speed and richness in details. Here, we show that beyond the pure diffraction information, XPD patterns exhibit pronounced circular dichroism in the angular distribution (CDAD) with asymmetries up to 80%, alongside with rapid variations on a small kll-scale (0.1 Å-1). Measurements with circularly-polarized hard X-rays (hν = 6 keV) for a number of core levels, including Si, Ge, Mo and W, prove that core-level CDAD is a general phenomenon that is independent of atomic number. The fine structure in CDAD is more pronounced compared to the corresponding intensity patterns. Additionally, they obey the same symmetry rules as found for atomic and molecular species, and valence bands. The CD is antisymmetric with respect to the mirror planes of the crystal, whose signatures are sharp zero lines. Calculations using both the Bloch-wave approach and one-step photoemission reveal the origin of the fine structure that represents the signature of Kikuchi diffraction. To disentangle the roles of photoexcitation and diffraction, XPD has been implemented into the Munich SPRKKR package to unify the one-step model of photoemission and multiple scattering theory.
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Affiliation(s)
- O Tkach
- Johannes Gutenberg-Universität, Institut für Physik, 55128 Mainz, Germany; Sumy State University, Rymskogo-Korsakova 2, 40007 Sumy, Ukraine.
| | - T-P Vo
- New Technologies - Research Centre, Univ. of West Bohemia, 30100 Pilsen, Czech Republic
| | - O Fedchenko
- Johannes Gutenberg-Universität, Institut für Physik, 55128 Mainz, Germany
| | - K Medjanik
- Johannes Gutenberg-Universität, Institut für Physik, 55128 Mainz, Germany
| | - Y Lytvynenko
- Johannes Gutenberg-Universität, Institut für Physik, 55128 Mainz, Germany; Institute of Magnetism of the NAS of Ukraine and MES of Ukraine, 03142 Kyiv, Ukraine
| | - S Babenkov
- Johannes Gutenberg-Universität, Institut für Physik, 55128 Mainz, Germany
| | - D Vasilyev
- Johannes Gutenberg-Universität, Institut für Physik, 55128 Mainz, Germany
| | - Q L Nguyen
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - T R F Peixoto
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - A Gloskowskii
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - C Schlueter
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - S Chernov
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - M Hoesch
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - D Kutnyakhov
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - M Scholz
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - L Wenthaus
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - N Wind
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany; Institut für Experimentalphysik, Universität Hamburg, 22761 Hamburg, Germany
| | - S Marotzke
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany; Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
| | - A Winkelmann
- Academic Centre for Materials and Nanotechn., Univ. of Science and Technology, Kraków, Poland
| | - K Rossnagel
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany; Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
| | - J Minár
- New Technologies - Research Centre, Univ. of West Bohemia, 30100 Pilsen, Czech Republic
| | - H-J Elmers
- Johannes Gutenberg-Universität, Institut für Physik, 55128 Mainz, Germany
| | - G Schönhense
- Johannes Gutenberg-Universität, Institut für Physik, 55128 Mainz, Germany
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8
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Datta S, Prakash Pandeya R, Bikash Dey A, Gloskovskii A, Schlueter C, Peixoto TRF, Singh A, Thamizhavel A, Maiti K. Layer-resolved electronic behavior in a Kondo lattice system, CeAgAs 2. J Phys Condens Matter 2023; 35:235601. [PMID: 36940482 DOI: 10.1088/1361-648x/acc5c9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 03/20/2023] [Indexed: 06/18/2023]
Abstract
We investigate the electronic structure of an antiferromagnetic Kondo lattice system CeAgAs2employing hardx-ray photoemission spectroscopy. CeAgAs2, an orthorhombic variant of HfCuSi2structure, exhibits antiferromagnetic ground state, Kondo like resistivity upturn and compensation of magnetic moments at low temperatures. The photoemission spectra obtained at different photon energies suggest termination of the cleaved surface at cis-trans-As layers. The depth-resolved data show significant surface-bulk differences in the As and Ce core level spectra. The As 2pbulk spectrum shows distinct two peaks corresponding to two different As layers. The peak at higher binding energy correspond to cis-trans-As layers and is weakly hybridized with the adjacent Ce layers. The As layers between Ce and Ag-layers possess close to trivalent configuration due to strong hybridization with the neighboring atoms and the corresponding feature appear at lower binding energy. Ce 3dcore level spectra show multiple features reflecting strong Ce-As hybridization and strong correlation. Intensef0peak is observed in the surface spectrum while it is insignificant in the bulk. In addition, we observe a features at binding energy lower than the well-screened feature indicating the presence of additional interactions. This feature becomes more intense in the bulk spectra suggesting it to be a bulk property. Increase in temperature leads to a spectral weight transfer to higher binding energies in the core level spectra and a depletion of spectral intensity at the Fermi level as expected in a Kondo material. These results reveal interesting surface-bulk differences, complex interplay of intra- and inter-layer covalency, and electron correlation in the electronic structure of this novel Kondo lattice system.
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Affiliation(s)
- Sawani Datta
- Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - Ram Prakash Pandeya
- Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - Arka Bikash Dey
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | - A Gloskovskii
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | - C Schlueter
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | - T R F Peixoto
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | - Ankita Singh
- Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - A Thamizhavel
- Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - Kalobaran Maiti
- Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
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9
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Kohantorabi M, Wagstaffe M, Creutzburg M, Ugolotti A, Kulkarni S, Jeromin A, Krekeler T, Feuerherd M, Herrmann A, Ebert G, Protzer U, Guédez G, Löw C, Thuenauer R, Schlueter C, Gloskovskii A, Keller TF, Di Valentin C, Stierle A, Noei H. Adsorption and Inactivation of SARS-CoV-2 on the Surface of Anatase TiO 2(101). ACS Appl Mater Interfaces 2023; 15:8770-8782. [PMID: 36723177 DOI: 10.1021/acsami.2c22078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
We investigated the adsorption of severe acute respiratory syndrome corona virus 2 (SARS-CoV-2), the virus responsible for the current pandemic, on the surface of the model catalyst TiO2(101) using atomic force microscopy, transmission electron microscopy, fluorescence microscopy, and X-ray photoelectron spectroscopy, accompanied by density functional theory calculations. Three different methods were employed to inactivate the virus after it was loaded on the surface of TiO2(101): (i) ethanol, (ii) thermal, and (iii) UV treatments. Microscopic studies demonstrate that the denatured spike proteins and other proteins in the virus structure readsorb on the surface of TiO2 under thermal and UV treatments. The interaction of the virus with the surface of TiO2 was different for the thermally and UV treated samples compared to the sample inactivated via ethanol treatment. AFM and TEM results on the UV-treated sample suggested that the adsorbed viral particles undergo damage and photocatalytic oxidation at the surface of TiO2(101) which can affect the structural proteins of SARS-CoV-2 and denature the spike proteins in 30 min. The role of Pd nanoparticles (NPs) was investigated in the interaction between SARS-CoV-2 and TiO2(101). The presence of Pd NPs enhanced the adsorption of the virus due to the possible interaction of the spike protein with the NPs. This study is the first investigation of the interaction of SARS-CoV-2 with the surface of single crystalline TiO2(101) as a potential candidate for virus deactivation applications. Clarification of the interaction of the virus with the surface of semiconductor oxides will aid in obtaining a deeper understanding of the chemical processes involved in photoinactivation of microorganisms, which is important for the design of effective photocatalysts for air purification and self-cleaning materials.
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Affiliation(s)
- Mona Kohantorabi
- Center for X-ray and Nano Science (CXNS), Deutsches Elektronen-Synchrotron (DESY), Notkestr. 85, Hamburg 22607, Germany
| | - Michael Wagstaffe
- Center for X-ray and Nano Science (CXNS), Deutsches Elektronen-Synchrotron (DESY), Notkestr. 85, Hamburg 22607, Germany
| | - Marcus Creutzburg
- Center for X-ray and Nano Science (CXNS), Deutsches Elektronen-Synchrotron (DESY), Notkestr. 85, Hamburg 22607, Germany
| | - Aldo Ugolotti
- Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca, Via Cozzi 55, Milano 20125, Italy
| | - Satishkumar Kulkarni
- Center for X-ray and Nano Science (CXNS), Deutsches Elektronen-Synchrotron (DESY), Notkestr. 85, Hamburg 22607, Germany
| | - Arno Jeromin
- Center for X-ray and Nano Science (CXNS), Deutsches Elektronen-Synchrotron (DESY), Notkestr. 85, Hamburg 22607, Germany
| | - Tobias Krekeler
- Electron Microscopy Unit, Hamburg University of Technology, Eissendorfer Strasse 42, Hamburg 21073, Germany
| | - Martin Feuerherd
- Institute of Virology, Technical University of Munich/Helmholtz Munich, Munich 81675, Germany
- Division of Gastroenterology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Alexander Herrmann
- Institute of Virology, Helmholtz Munich, Ingolstädter Landstraße 1, Neuherberg 85764, Germany
| | - Gregor Ebert
- Institute of Virology, Technical University of Munich/Helmholtz Munich, Munich 81675, Germany
| | - Ulrike Protzer
- Institute of Virology, Technical University of Munich/Helmholtz Munich, Munich 81675, Germany
| | - Gabriela Guédez
- Centre for Structural Systems Biology (CSSB), Deutsches Elektronen-Synchrotron (DESY), EMBL Hamburg, Notkestr. 85, Hamburg 22607, Germany
| | - Christian Löw
- Centre for Structural Systems Biology (CSSB), Deutsches Elektronen-Synchrotron (DESY), EMBL Hamburg, Notkestr. 85, Hamburg 22607, Germany
| | - Roland Thuenauer
- Technology Platform Light Microscopy and Image Analysis (TP MIA), Leibniz Institute for Experimental Virology (HPI), Hamburg 20251, Germany
- Centre for Structural Systems Biology (CSSB), Notkestr. 85, Hamburg 22607, Germany
| | - Christoph Schlueter
- Deutsches Elektronen-Synchrotron (DESY), Notkestr. 85, Hamburg 22607, Germany
| | - Andrei Gloskovskii
- Deutsches Elektronen-Synchrotron (DESY), Notkestr. 85, Hamburg 22607, Germany
| | - Thomas F Keller
- Center for X-ray and Nano Science (CXNS), Deutsches Elektronen-Synchrotron (DESY), Notkestr. 85, Hamburg 22607, Germany
- Department of Physics, University of Hamburg, Notkestraße 9-11, Hamburg 22607, Germany
| | - Cristiana Di Valentin
- Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca, Via Cozzi 55, Milano 20125, Italy
| | - Andreas Stierle
- Center for X-ray and Nano Science (CXNS), Deutsches Elektronen-Synchrotron (DESY), Notkestr. 85, Hamburg 22607, Germany
- Department of Physics, University of Hamburg, Notkestraße 9-11, Hamburg 22607, Germany
| | - Heshmat Noei
- Center for X-ray and Nano Science (CXNS), Deutsches Elektronen-Synchrotron (DESY), Notkestr. 85, Hamburg 22607, Germany
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10
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Ratcliff LE, Oshima T, Nippert F, Janzen BM, Kluth E, Goldhahn R, Feneberg M, Mazzolini P, Bierwagen O, Wouters C, Nofal M, Albrecht M, Swallow JEN, Jones LAH, Thakur PK, Lee TL, Kalha C, Schlueter C, Veal TD, Varley JB, Wagner MR, Regoutz A. Tackling Disorder in γ-Ga 2 O 3. Adv Mater 2022; 34:e2204217. [PMID: 35866491 DOI: 10.1002/adma.202204217] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 07/05/2022] [Indexed: 06/15/2023]
Abstract
Ga2 O3 and its polymorphs are attracting increasing attention. The rich structural space of polymorphic oxide systems such as Ga2 O3 offers potential for electronic structure engineering, which is of particular interest for a range of applications, such as power electronics. γ-Ga2 O3 presents a particular challenge across synthesis, characterization, and theory due to its inherent disorder and resulting complex structure-electronic-structure relationship. Here, density functional theory is used in combination with a machine-learning approach to screen nearly one million potential structures, thereby developing a robust atomistic model of the γ-phase. Theoretical results are compared with surface and bulk sensitive soft and hard X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, spectroscopic ellipsometry, and photoluminescence excitation spectroscopy experiments representative of the occupied and unoccupied states of γ-Ga2 O3 . The first onset of strong absorption at room temperature is found at 5.1 eV from spectroscopic ellipsometry, which agrees well with the excitation maximum at 5.17 eV obtained by photoluminescence excitation spectroscopy, where the latter shifts to 5.33 eV at 5 K. This work presents a leap forward in the treatment of complex, disordered oxides and is a crucial step toward exploring how their electronic structure can be understood in terms of local coordination and overall structure.
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Affiliation(s)
- Laura E Ratcliff
- Department of Materials, Imperial College London, London, SW7 2AZ, UK
- Center for Computational Chemistry, School of Chemistry, University of Bristol, Bristol, BS8 1TS, UK
| | - Takayoshi Oshima
- Department of Electrical and Electronic Engineering, Saga University, Saga, 840-8502, Japan
| | - Felix Nippert
- Technische Universität Berlin, Institute of Solid State Physics, Hardenbergstrasse 36, 10623, Berlin, Germany
| | - Benjamin M Janzen
- Technische Universität Berlin, Institute of Solid State Physics, Hardenbergstrasse 36, 10623, Berlin, Germany
| | - Elias Kluth
- Institut für Physik, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, 39106, Magdeburg, Germany
| | - Rüdiger Goldhahn
- Institut für Physik, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, 39106, Magdeburg, Germany
| | - Martin Feneberg
- Institut für Physik, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, 39106, Magdeburg, Germany
| | - Piero Mazzolini
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, 10117, Berlin, Germany
| | - Oliver Bierwagen
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, 10117, Berlin, Germany
| | - Charlotte Wouters
- Leibniz-Institut für Kristallzüchtung, Max-Born-Str. 2, 12489, Berlin, Germany
| | - Musbah Nofal
- Leibniz-Institut für Kristallzüchtung, Max-Born-Str. 2, 12489, Berlin, Germany
| | - Martin Albrecht
- Leibniz-Institut für Kristallzüchtung, Max-Born-Str. 2, 12489, Berlin, Germany
| | - Jack E N Swallow
- Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH, UK
| | - Leanne A H Jones
- Stephenson Institute for Renewable Energy and Department of Physics, University of Liverpool, Liverpool, L69 7ZF, UK
| | - Pardeep K Thakur
- Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK
| | - Tien-Lin Lee
- Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK
| | - Curran Kalha
- Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, UK
| | - Christoph Schlueter
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607, Hamburg, Germany
| | - Tim D Veal
- Stephenson Institute for Renewable Energy and Department of Physics, University of Liverpool, Liverpool, L69 7ZF, UK
| | - Joel B Varley
- Lawrence Livermore National Laboratory, Livermore, CA, 94550, USA
| | - Markus R Wagner
- Technische Universität Berlin, Institute of Solid State Physics, Hardenbergstrasse 36, 10623, Berlin, Germany
| | - Anna Regoutz
- Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, UK
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11
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Kubitza N, Reitz A, Zieschang AM, Pazniak H, Albert B, Kalha C, Schlueter C, Regoutz A, Wiedwald U, Birkel CS. From MAX Phase Carbides to Nitrides: Synthesis of V 2GaC, V 2GaN, and the Carbonitride V 2GaC 1-xN x. Inorg Chem 2022; 61:10634-10641. [PMID: 35775787 DOI: 10.1021/acs.inorgchem.2c00200] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The research in MAX phases is mainly concentrated on the investigation of carbides rather than nitrides (currently >150 carbides and only <15 nitrides) that are predominantly synthesized by conventional solid-state techniques. This is not surprising since the preparation of nitrides and carbonitrides is more demanding due to the high stability and low diffusion rate of nitrogen-containing compounds. This leads to several drawbacks concerning potential variations in the chemical composition of the MAX phases as well as control of morphology, the two aspects that directly affect the resulting materials properties. Here, we report how alternative solid-state hybrid techniques solve these limitations by combining conventional techniques with nonconventional precursor synthesis methods, such as the "urea-glass" sol-gel or liquid ammonia method. We demonstrate the synthesis and morphology control within the V-Ga-C-N system by preparing the MAX phase carbide and nitride─the latter in the form of bulkier and more defined smaller particle structures─as well as a hitherto unknown carbonitride V2GaC1-xNx MAX phase. This shows the versatility of hybrid methods starting, for example, from wet chemically obtained precursors that already contain all of the ingredients needed for carbonitride formation. All products are characterized in detail by X-ray powder diffraction, electron microscopy, and electron and X-ray photoelectron spectroscopies to confirm their structure and morphology and to detect subtle differences between the different chemical compositions.
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Affiliation(s)
- Niels Kubitza
- Eduard Zintl Institute of Inorganic and Physical Chemistry, Technische Universität Darmstadt, Alarich-Weiss-Straße 12, 64287 Darmstadt, Germany
| | - Andreas Reitz
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85282, United States
| | - Anne-Marie Zieschang
- Eduard Zintl Institute of Inorganic and Physical Chemistry, Technische Universität Darmstadt, Alarich-Weiss-Straße 12, 64287 Darmstadt, Germany
| | - Hanna Pazniak
- Faculty of Physics and Center for Nanointegration Duisburg-Essen, University of Duisburg-Essen, 47057 Duisburg, Germany
| | - Barbara Albert
- Eduard Zintl Institute of Inorganic and Physical Chemistry, Technische Universität Darmstadt, Alarich-Weiss-Straße 12, 64287 Darmstadt, Germany
| | - Curran Kalha
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Christoph Schlueter
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Anna Regoutz
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Ulf Wiedwald
- Faculty of Physics and Center for Nanointegration Duisburg-Essen, University of Duisburg-Essen, 47057 Duisburg, Germany
| | - Christina S Birkel
- Eduard Zintl Institute of Inorganic and Physical Chemistry, Technische Universität Darmstadt, Alarich-Weiss-Straße 12, 64287 Darmstadt, Germany.,School of Molecular Sciences, Arizona State University, Tempe, Arizona 85282, United States
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12
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Shipilin M, Degerman D, Lömker P, Goodwin CM, Rodrigues GLS, Wagstaffe M, Gladh J, Wang HY, Stierle A, Schlueter C, Pettersson LGM, Nilsson A, Amann P. In Situ Surface-Sensitive Investigation of Multiple Carbon Phases on Fe(110) in the Fischer–Tropsch Synthesis. ACS Catal 2022; 12:7609-7621. [PMID: 35815066 PMCID: PMC9254136 DOI: 10.1021/acscatal.2c00905] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 05/31/2022] [Indexed: 11/28/2022]
Abstract
![]()
Carbide formation
on iron-based catalysts is an integral and, arguably,
the most important part of the Fischer–Tropsch synthesis process,
converting CO and H2 into synthetic fuels and numerous
valuable chemicals. Here, we report an in situ surface-sensitive study
of the effect of pressure, temperature, time, and gas feed composition
on the growth dynamics of two distinct iron–carbon phases with
the octahedral and trigonal prismatic coordination of carbon sites
on an Fe(110) single crystal acting as a model catalyst. Using a combination
of state-of-the-art X-ray photoelectron spectroscopy at an unprecedentedly
high pressure, high-energy surface X-ray diffraction, mass spectrometry,
and theoretical calculations, we reveal the details of iron surface
carburization and product formation under semirealistic conditions.
We provide a detailed insight into the state of the catalyst’s
surface in relation to the reaction.
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Affiliation(s)
- Mikhail Shipilin
- Department of Physics, Stockholm University, 10691 Stockholm, Sweden
| | - David Degerman
- Department of Physics, Stockholm University, 10691 Stockholm, Sweden
| | - Patrick Lömker
- Photon Science, Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | | | | | - Michael Wagstaffe
- DESY NanoLab, Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | - Jörgen Gladh
- Department of Physics, Stockholm University, 10691 Stockholm, Sweden
- PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, 94305 California, United States
| | - Hsin-Yi Wang
- Department of Physics, Stockholm University, 10691 Stockholm, Sweden
| | - Andreas Stierle
- DESY NanoLab, Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
- Physics Department, University of Hamburg, 20148 Hamburg, Germany
| | - Christoph Schlueter
- Photon Science, Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | | | - Anders Nilsson
- Department of Physics, Stockholm University, 10691 Stockholm, Sweden
| | - Peter Amann
- Department of Physics, Stockholm University, 10691 Stockholm, Sweden
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13
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Amann P, Klötzer B, Degerman D, Köpfle N, Götsch T, Lömker P, Rameshan C, Ploner K, Bikaljevic D, Wang HY, Soldemo M, Shipilin M, Goodwin CM, Gladh J, Halldin Stenlid J, Börner M, Schlueter C, Nilsson A. The state of zinc in methanol synthesis over a Zn/ZnO/Cu(211) model catalyst. Science 2022; 376:603-608. [PMID: 35511988 DOI: 10.1126/science.abj7747] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The active chemical state of zinc (Zn) in a zinc-copper (Zn-Cu) catalyst during carbon dioxide/carbon monoxide (CO2/CO) hydrogenation has been debated to be Zn oxide (ZnO) nanoparticles, metallic Zn, or a Zn-Cu surface alloy. We used x-ray photoelectron spectroscopy at 180 to 500 millibar to probe the nature of Zn and reaction intermediates during CO2/CO hydrogenation over Zn/ZnO/Cu(211), where the temperature is sufficiently high for the reaction to rapidly turn over, thus creating an almost adsorbate-free surface. Tuning of the grazing incidence angle makes it possible to achieve either surface or bulk sensitivity. Hydrogenation of CO2 gives preference to ZnO in the form of clusters or nanoparticles, whereas in pure CO a surface Zn-Cu alloy becomes more prominent. The results reveal a specific role of CO in the formation of the Zn-Cu surface alloy as an active phase that facilitates efficient CO2 methanol synthesis.
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Affiliation(s)
- Peter Amann
- Department of Physics, Stockholm University, AlbaNova University Center, 10691 Stockholm, Sweden
| | - Bernhard Klötzer
- Institute of Physical Chemistry, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria
| | - David Degerman
- Department of Physics, Stockholm University, AlbaNova University Center, 10691 Stockholm, Sweden
| | - Norbert Köpfle
- Institute of Physical Chemistry, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria
| | - Thomas Götsch
- Department of Inorganic Chemistry, Fritz Haber Institute of the Max-Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
| | - Patrick Lömker
- Department of Physics, Stockholm University, AlbaNova University Center, 10691 Stockholm, Sweden.,Photon Science, Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Christoph Rameshan
- Institute of Materials Chemistry, Technische Universität Wien, Getreidemarkt 9/BC/01, 1060 Vienna, Austria
| | - Kevin Ploner
- Institute of Physical Chemistry, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria
| | - Djuro Bikaljevic
- Institute of Physical Chemistry, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria
| | - Hsin-Yi Wang
- Department of Physics, Stockholm University, AlbaNova University Center, 10691 Stockholm, Sweden
| | - Markus Soldemo
- Department of Physics, Stockholm University, AlbaNova University Center, 10691 Stockholm, Sweden
| | - Mikhail Shipilin
- Department of Physics, Stockholm University, AlbaNova University Center, 10691 Stockholm, Sweden
| | - Christopher M Goodwin
- Department of Physics, Stockholm University, AlbaNova University Center, 10691 Stockholm, Sweden
| | - Jörgen Gladh
- Department of Physics, Stockholm University, AlbaNova University Center, 10691 Stockholm, Sweden
| | - Joakim Halldin Stenlid
- Department of Physics, Stockholm University, AlbaNova University Center, 10691 Stockholm, Sweden
| | - Mia Börner
- Department of Physics, Stockholm University, AlbaNova University Center, 10691 Stockholm, Sweden
| | - Christoph Schlueter
- Photon Science, Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Anders Nilsson
- Department of Physics, Stockholm University, AlbaNova University Center, 10691 Stockholm, Sweden
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14
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Degerman D, Shipilin M, Lömker P, Goodwin CM, Gericke SM, Hejral U, Gladh J, Wang HY, Schlueter C, Nilsson A, Amann P. Operando Observation of Oxygenated Intermediates during CO Hydrogenation on Rh Single Crystals. J Am Chem Soc 2022; 144:7038-7042. [PMID: 35394273 PMCID: PMC9052753 DOI: 10.1021/jacs.2c00300] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
The CO hydrogenation
reaction over the Rh(111) and (211) surfaces
has been investigated operando by X-ray photoelectron spectroscopy
at a pressure of 150 mbar. Observations of the resting state of the
catalyst give mechanistic insight into the selectivity of Rh for generating
ethanol from CO hydrogenation. This study shows that the Rh(111) surface
does not dissociate all CO molecules before hydrogenation of the O
and C atoms, which allows methoxy and other both oxygenated and hydrogenated
species to be visible in the photoelectron spectra.
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Affiliation(s)
- David Degerman
- Department of Physics, AlbaNova University Center, Stockholm University, Roslagstullsbacken 21, Stockholm 114 21, Sweden
| | - Mikhail Shipilin
- Department of Physics, AlbaNova University Center, Stockholm University, Roslagstullsbacken 21, Stockholm 114 21, Sweden
| | - Patrick Lömker
- Department of Physics, AlbaNova University Center, Stockholm University, Roslagstullsbacken 21, Stockholm 114 21, Sweden
| | - Christopher M Goodwin
- Department of Physics, AlbaNova University Center, Stockholm University, Roslagstullsbacken 21, Stockholm 114 21, Sweden
| | - Sabrina M Gericke
- Department of Physics Combustion Physics, Lund University, Professorsgatan 1, Lund 223 63, Sweden
| | - Uta Hejral
- Division of Synchrotron Radiation Research, Lund University, Professorsgatan 1, Lund 223 63, Sweden
| | - Jörgen Gladh
- Department of Physics, AlbaNova University Center, Stockholm University, Roslagstullsbacken 21, Stockholm 114 21, Sweden
| | - Hsin-Yi Wang
- Department of Physics, AlbaNova University Center, Stockholm University, Roslagstullsbacken 21, Stockholm 114 21, Sweden
| | - Christoph Schlueter
- Photon Science, Deutches Elektronen Synchrotron DESY, Notkestraße 85, Hamburg 226 07, Germany
| | - Anders Nilsson
- Department of Physics, AlbaNova University Center, Stockholm University, Roslagstullsbacken 21, Stockholm 114 21, Sweden
| | - Peter Amann
- Department of Physics, AlbaNova University Center, Stockholm University, Roslagstullsbacken 21, Stockholm 114 21, Sweden
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15
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Wang H, Soldemo M, Degerman D, Lömker P, Schlueter C, Nilsson A, Amann P. Direct Evidence of Subsurface Oxygen Formation in Oxide‐Derived Cu by X‐ray Photoelectron Spectroscopy. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202111021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Hsin‐Yi Wang
- Department of Physics AlbaNova University Center Stockholm University 10691 Stockholm Sweden
| | - Markus Soldemo
- Department of Physics AlbaNova University Center Stockholm University 10691 Stockholm Sweden
| | - David Degerman
- Department of Physics AlbaNova University Center Stockholm University 10691 Stockholm Sweden
| | - Patrick Lömker
- Department of Physics AlbaNova University Center Stockholm University 10691 Stockholm Sweden
- Photon Science Deutsches Elektronen-Synchrotron (DESY) 22607 Hamburg Germany
| | - Christoph Schlueter
- Photon Science Deutsches Elektronen-Synchrotron (DESY) 22607 Hamburg Germany
| | - Anders Nilsson
- Department of Physics AlbaNova University Center Stockholm University 10691 Stockholm Sweden
| | - Peter Amann
- Department of Physics AlbaNova University Center Stockholm University 10691 Stockholm Sweden
- Current address: Scienta Omicron AB Danmarksgatan 22 75323 Uppsala Sweden
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16
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Wang H, Soldemo M, Degerman D, Lömker P, Schlueter C, Nilsson A, Amann P. Back Cover: Direct Evidence of Subsurface Oxygen Formation in Oxide‐Derived Cu by X‐ray Photoelectron Spectroscopy (Angew. Chem. Int. Ed. 3/2022). Angew Chem Int Ed Engl 2022. [DOI: 10.1002/anie.202116138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Hsin‐Yi Wang
- Department of Physics AlbaNova University Center Stockholm University 10691 Stockholm Sweden
| | - Markus Soldemo
- Department of Physics AlbaNova University Center Stockholm University 10691 Stockholm Sweden
| | - David Degerman
- Department of Physics AlbaNova University Center Stockholm University 10691 Stockholm Sweden
| | - Patrick Lömker
- Department of Physics AlbaNova University Center Stockholm University 10691 Stockholm Sweden
- Photon Science Deutsches Elektronen-Synchrotron (DESY) 22607 Hamburg Germany
| | - Christoph Schlueter
- Photon Science Deutsches Elektronen-Synchrotron (DESY) 22607 Hamburg Germany
| | - Anders Nilsson
- Department of Physics AlbaNova University Center Stockholm University 10691 Stockholm Sweden
| | - Peter Amann
- Department of Physics AlbaNova University Center Stockholm University 10691 Stockholm Sweden
- Current address: Scienta Omicron AB Danmarksgatan 22 75323 Uppsala Sweden
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17
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Wang H, Soldemo M, Degerman D, Lömker P, Schlueter C, Nilsson A, Amann P. Rücktitelbild: Direct Evidence of Subsurface Oxygen Formation in Oxide‐Derived Cu by X‐ray Photoelectron Spectroscopy (Angew. Chem. 3/2022). Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202116138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Hsin‐Yi Wang
- Department of Physics AlbaNova University Center Stockholm University 10691 Stockholm Sweden
| | - Markus Soldemo
- Department of Physics AlbaNova University Center Stockholm University 10691 Stockholm Sweden
| | - David Degerman
- Department of Physics AlbaNova University Center Stockholm University 10691 Stockholm Sweden
| | - Patrick Lömker
- Department of Physics AlbaNova University Center Stockholm University 10691 Stockholm Sweden
- Photon Science Deutsches Elektronen-Synchrotron (DESY) 22607 Hamburg Germany
| | - Christoph Schlueter
- Photon Science Deutsches Elektronen-Synchrotron (DESY) 22607 Hamburg Germany
| | - Anders Nilsson
- Department of Physics AlbaNova University Center Stockholm University 10691 Stockholm Sweden
| | - Peter Amann
- Department of Physics AlbaNova University Center Stockholm University 10691 Stockholm Sweden
- Current address: Scienta Omicron AB Danmarksgatan 22 75323 Uppsala Sweden
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18
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Wang HY, Soldemo M, Degerman D, Lömker P, Schlueter C, Nilsson A, Amann P. Direct Evidence of Subsurface Oxygen Formation in Oxide-Derived Cu by X-ray Photoelectron Spectroscopy. Angew Chem Int Ed Engl 2021; 61:e202111021. [PMID: 34758161 PMCID: PMC9299841 DOI: 10.1002/anie.202111021] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 10/19/2021] [Indexed: 11/30/2022]
Abstract
Subsurface oxygen has been proposed to be crucial in oxide‐derived copper (OD‐Cu) electrocatalysts for enhancing the binding of CO intermediates during CO2 reduction reaction (CO2RR). However, the presence of such oxygen species under reductive conditions still remains debated. In this work, the existence of subsurface oxygen is validated by grazing incident hard X‐ray photoelectron spectroscopy, where OD‐Cu was prepared by reduction of Cu oxide with H2 without exposing to air. The results suggest two types of subsurface oxygen embedded between the fully reduced metallic surface and the Cu2O buried beneath: (i) oxygen staying at lattice defects and/or vacancies in the surface‐most region and (ii) interstitial oxygen intercalated in metal structure. This study adds convincing support to the presence of subsurface oxygen in OD‐Cu, which previously has been suggested to play an important role to mitigate the σ‐repulsion of Cu for CO intermediates in CO2RR.
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Affiliation(s)
- Hsin-Yi Wang
- Department of Physics, AlbaNova University Center, Stockholm University, 10691, Stockholm, Sweden
| | - Markus Soldemo
- Department of Physics, AlbaNova University Center, Stockholm University, 10691, Stockholm, Sweden
| | - David Degerman
- Department of Physics, AlbaNova University Center, Stockholm University, 10691, Stockholm, Sweden
| | - Patrick Lömker
- Department of Physics, AlbaNova University Center, Stockholm University, 10691, Stockholm, Sweden.,Photon Science, Deutsches Elektronen-Synchrotron (DESY), 22607, Hamburg, Germany
| | - Christoph Schlueter
- Photon Science, Deutsches Elektronen-Synchrotron (DESY), 22607, Hamburg, Germany
| | - Anders Nilsson
- Department of Physics, AlbaNova University Center, Stockholm University, 10691, Stockholm, Sweden
| | - Peter Amann
- Department of Physics, AlbaNova University Center, Stockholm University, 10691, Stockholm, Sweden.,Current address: Scienta Omicron AB, Danmarksgatan 22, 75323, Uppsala, Sweden
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19
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Dmitriyeva A, Mikheev V, Zarubin S, Chouprik A, Vinai G, Polewczyk V, Torelli P, Matveyev Y, Schlueter C, Karateev I, Yang Q, Chen Z, Tao L, Tsymbal EY, Zenkevich A. Magnetoelectric Coupling at the Ni/Hf 0.5Zr 0.5O 2 Interface. ACS Nano 2021; 15:14891-14902. [PMID: 34468129 DOI: 10.1021/acsnano.1c05001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Composite multiferroics containing ferroelectric and ferromagnetic components often have much larger magnetoelectric coupling compared to their single-phase counterparts. Doped or alloyed HfO2-based ferroelectrics may serve as a promising component in composite multiferroic structures potentially feasible for technological applications. Recently, a strong charge-mediated magnetoelectric coupling at the Ni/HfO2 interface has been predicted using density functional theory calculations. Here, we report on the experimental evidence of such magnetoelectric coupling at the Ni/Hf0.5Zr0.5O2(HZO) interface. Using a combination of operando XAS/XMCD and HAXPES/MCDAD techniques, we probe element-selectively the local magnetic properties at the Ni/HZO interface in functional Au/Co/Ni/HZO/W capacitors and demonstrate clear evidence of the ferroelectric polarization effect on the magnetic response of a nanometer-thick Ni marker layer. The observed magnetoelectric effect and the electronic band lineup of the Ni/HZO interface are interpreted based on the results of our theoretical modeling. It elucidates the critical role of an ultrathin NiO interlayer, which controls the sign of the magnetoelectric effect as well as provides a realistic band offset at the Ni/HZO interface, in agreement with the experiment. Our results hold promise for the use of ferroelectric HfO2-based composite multiferroics for the design of multifunctional devices compatible with modern semiconductor technology.
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Affiliation(s)
- Anna Dmitriyeva
- Moscow Institute of Physics and Technology, 9, Institutskiy lane, Dolgoprudny, Moscow Region, 141700, Russia
| | - Vitalii Mikheev
- Moscow Institute of Physics and Technology, 9, Institutskiy lane, Dolgoprudny, Moscow Region, 141700, Russia
| | - Sergei Zarubin
- Moscow Institute of Physics and Technology, 9, Institutskiy lane, Dolgoprudny, Moscow Region, 141700, Russia
| | - Anastasia Chouprik
- Moscow Institute of Physics and Technology, 9, Institutskiy lane, Dolgoprudny, Moscow Region, 141700, Russia
| | - Giovanni Vinai
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, Area Science Park, S.S. 14 km 163.5, Trieste I-34149, Italy
| | - Vincent Polewczyk
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, Area Science Park, S.S. 14 km 163.5, Trieste I-34149, Italy
| | - Piero Torelli
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, Area Science Park, S.S. 14 km 163.5, Trieste I-34149, Italy
| | - Yury Matveyev
- Deutsches Elektronen-Synchrotron, 85 Notkestraße, Hamburg, D-22607, Germany
| | | | - Igor Karateev
- National Research Center "Kurchatov Institute", Moscow, 123182, Russia
| | - Qiong Yang
- School of Materials Science and Engineering, Xiangtan University, Xiangtan, Hunan 411105, China
| | - Zhaojin Chen
- School of Materials Science and Engineering, Xiangtan University, Xiangtan, Hunan 411105, China
| | - Lingling Tao
- Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Evgeny Y Tsymbal
- Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Andrei Zenkevich
- Moscow Institute of Physics and Technology, 9, Institutskiy lane, Dolgoprudny, Moscow Region, 141700, Russia
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20
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Blomberg S, Hejral U, Shipilin M, Albertin S, Karlsson H, Hulteberg C, Lömker P, Goodwin C, Degerman D, Gustafson J, Schlueter C, Nilsson A, Lundgren E, Amann P. Bridging the Pressure Gap in CO Oxidation. ACS Catal 2021; 11:9128-9135. [PMID: 34476111 PMCID: PMC8397290 DOI: 10.1021/acscatal.1c00806] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 06/11/2021] [Indexed: 11/28/2022]
Abstract
Performing fundamental operando catalysis studies under realistic conditions is a key to further develop and increase the efficiency of industrial catalysts. Operando X-ray photoelectron spectroscopy (XPS) experiments have been limited to pressures, and the relevance for industrial applications has been questioned. Herein, we report on the CO oxidation experiment on Pd(100) performed at a total pressure of 1 bar using XPS. We investigate the light-off regime and the surface chemical composition at the atomistic level in the highly active phase. Furthermore, the observed gas-phase photoemission peaks of CO2, CO, and O2 indicate that the kinetics of the reaction during the light-off regime can be followed operando, and by studying the reaction rate of the reaction, the activation energy is calculated. The reaction was preceded by an in situ oxidation study in 7% O2 in He and a total pressure of 70 mbar to confirm the surface sensitivity and assignment of the oxygen-induced photoemission peaks. However, oxygen-induced photoemission peaks were not observed during the reaction studies, but instead, a metallic Pd phase is present in the highly active regime under the conditions applied. The novel XPS setup utilizes hard X-rays to enable high-pressure studies, combined with a grazing incident angle to increase the surface sensitivity of the measurement. Our findings demonstrate the possibilities of achieving chemical information of the catalyst, operando, on an atomistic level, under industrially relevant conditions.
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Affiliation(s)
- Sara Blomberg
- Department of Chemical Engineering, Lund University, Lund 221 00, Sweden
| | - Uta Hejral
- Department of Physics, Lund University, Lund 221 00, Sweden
| | - Mikhail Shipilin
- Department of Physics, AlbaNova University Center, Stockholm University, Stockholm 10691, Sweden
| | | | - Hanna Karlsson
- Department of Chemical Engineering, Lund University, Lund 221 00, Sweden
| | | | - Patrick Lömker
- Photon Science, Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, Hamburg 22607, Germany
| | - Christopher Goodwin
- Department of Physics, AlbaNova University Center, Stockholm University, Stockholm 10691, Sweden
| | - David Degerman
- Department of Physics, AlbaNova University Center, Stockholm University, Stockholm 10691, Sweden
| | | | - Christoph Schlueter
- Photon Science, Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, Hamburg 22607, Germany
| | - Anders Nilsson
- Department of Physics, AlbaNova University Center, Stockholm University, Stockholm 10691, Sweden
| | - Edvin Lundgren
- Department of Physics, Lund University, Lund 221 00, Sweden
| | - Peter Amann
- Department of Physics, AlbaNova University Center, Stockholm University, Stockholm 10691, Sweden
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21
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Büschges MI, Hoffmann RC, Regoutz A, Schlueter C, Schneider JJ. Cover Feature: Atomic Layer Deposition of Ternary Indium/Tin/Aluminum Oxide Thin Films, Their Characterization and Transistor Performance under Illumination. (Chem. Eur. J. 38/2021). Chemistry 2021. [DOI: 10.1002/chem.202102030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- M. Isabelle Büschges
- Fachbereich Chemie Eduard-Zintl-Institut für Anorganische und Physikalische Chemie Technische Universität Darmstadt Alarich-Weiss-Straße 12 64287 Darmstadt Germany
| | - Rudolf C. Hoffmann
- Fachbereich Chemie Eduard-Zintl-Institut für Anorganische und Physikalische Chemie Technische Universität Darmstadt Alarich-Weiss-Straße 12 64287 Darmstadt Germany
| | - Anna Regoutz
- Department of Chemistry University College London 20 Gordon Street WC1H 0AJ London UK
| | | | - Jörg J. Schneider
- Fachbereich Chemie Eduard-Zintl-Institut für Anorganische und Physikalische Chemie Technische Universität Darmstadt Alarich-Weiss-Straße 12 64287 Darmstadt Germany
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22
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Büschges MI, Hoffmann RC, Regoutz A, Schlueter C, Schneider JJ. Atomic Layer Deposition of Ternary Indium/Tin/Aluminum Oxide Thin Films, Their Characterization and Transistor Performance under Illumination. Chemistry 2021; 27:9791-9800. [PMID: 34002896 PMCID: PMC8362207 DOI: 10.1002/chem.202101126] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Indexed: 11/23/2022]
Abstract
Multilayered heterostructures comprising of In2 O3 , SnO2 , and Al2 O3 were studied for their application in thin-film transistors (TFT). The compositional influence of tin oxide on the properties of the thin-film, as well as on the TFT characteristics is investigated. The heterostructures are fabricated by atomic layer deposition (ALD) at 200 °C, employing trimethylindium (TMI), tetrakis(dimethylamino)tin (TDMASn), trimethylaluminum (TMA), and water as precursors. After post-deposition annealing at 400 °C the thin-films are found to be amorphous, however, they show a discrete layer structure of the individual oxides of uniform film thickness and high optical transparency in the visible region. Incorporation of only two monolayers of Al2 O3 in the active semiconducting layer the formation of oxygen vacancies can be effectively suppressed, resulting in an improved semiconducting and switching behavior. The heterostacks comprising of In2 O3 /SnO2 /Al2 O3 are incorporated into TFT devices, exhibiting a saturation field-effect mobility (μsat ) of 2.0 cm2 ⋅ V-1 s-1 , a threshold-voltage (Vth ) of 8.6 V, a high current on/off ratio (IOn /IOff ) of 1.0×107 , and a subthreshold swing (SS) of 485 mV ⋅ dec-1 . The stability of the TFT under illumination is also altered to a significant extent. A change in the transfer characteristic towards conductive behavior is evident when illuminated with light of an energy of 3.1 eV (400 nm).
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Affiliation(s)
- M. Isabelle Büschges
- Fachbereich ChemieEduard-Zintl-Institut für Anorganische und Physikalische ChemieTechnische Universität DarmstadtAlarich-Weiss-Straße 1264287DarmstadtGermany
| | - Rudolf C. Hoffmann
- Fachbereich ChemieEduard-Zintl-Institut für Anorganische und Physikalische ChemieTechnische Universität DarmstadtAlarich-Weiss-Straße 1264287DarmstadtGermany
| | - Anna Regoutz
- Department of ChemistryUniversity College London20 Gordon StreetWC1H 0AJLondonUK
| | | | - Jörg J. Schneider
- Fachbereich ChemieEduard-Zintl-Institut für Anorganische und Physikalische ChemieTechnische Universität DarmstadtAlarich-Weiss-Straße 1264287DarmstadtGermany
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23
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Goodwin CM, Shipilin M, Albertin S, Hejral U, Lömker P, Wang HY, Blomberg S, Degerman D, Schlueter C, Nilsson A, Lundgren E, Amann P. The Structure of the Active Pd State During Catalytic Carbon Monoxide Oxidization. J Phys Chem Lett 2021; 12:4461-4465. [PMID: 33955763 PMCID: PMC8279738 DOI: 10.1021/acs.jpclett.1c00620] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 04/21/2021] [Indexed: 06/12/2023]
Abstract
Using grazing incidence X-rays and X-ray photoelectron spectroscopy during the mass transfer limited catalytic oxidation of CO, the long-range surface structure of Pd(100) was investigated. Under the reaction conditions of 50:4 O2 to CO, 300 mbar pressure, and temperatures between 200 and 450 °C, the surface structure resulting from oxidation and the subsequent oxide reduction was elucidated. The reduction cycle was halted, and while under reaction conditions, angle-dependent X-ray photoelectron spectroscopy close to the critical angle of Pd and modeling of the data was performed. Two proposed models for the system were compared. The suggestion with the metallic islands formed on top of the oxide island was shown to be consistent with the data.
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Affiliation(s)
| | - Mikhail Shipilin
- Department
of Physics, Stockholm University, 10691 Stockholm, Sweden
| | - Stefano Albertin
- Synchrotron
Radiation Research, Lund University, 22100 Lund, Sweden
| | - Uta Hejral
- Synchrotron
Radiation Research, Lund University, 22100 Lund, Sweden
| | - Patrick Lömker
- Photon
Science, Deutsches Elektronen-Synchrotron
(DESY), 22607 Hamburg, Germany
| | - Hsin-Yi Wang
- Department
of Physics, Stockholm University, 10691 Stockholm, Sweden
| | - Sara Blomberg
- Department
of Chemical Engineering, Lund University, 22100 Lund, Sweden
| | - David Degerman
- Department
of Physics, Stockholm University, 10691 Stockholm, Sweden
| | - Christoph Schlueter
- Photon
Science, Deutsches Elektronen-Synchrotron
(DESY), 22607 Hamburg, Germany
| | - Anders Nilsson
- Department
of Physics, Stockholm University, 10691 Stockholm, Sweden
| | - Edvin Lundgren
- Synchrotron
Radiation Research, Lund University, 22100 Lund, Sweden
| | - Peter Amann
- Department
of Physics, Stockholm University, 10691 Stockholm, Sweden
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24
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Kalha C, Fernando NK, Bhatt P, Johansson FOL, Lindblad A, Rensmo H, Medina LZ, Lindblad R, Siol S, Jeurgens LPH, Cancellieri C, Rossnagel K, Medjanik K, Schönhense G, Simon M, Gray AX, Nemšák S, Lömker P, Schlueter C, Regoutz A. Hard x-ray photoelectron spectroscopy: a snapshot of the state-of-the-art in 2020. J Phys Condens Matter 2021; 33:233001. [PMID: 33647896 DOI: 10.1088/1361-648x/abeacd] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 03/01/2021] [Indexed: 06/12/2023]
Abstract
Hard x-ray photoelectron spectroscopy (HAXPES) is establishing itself as an essential technique for the characterisation of materials. The number of specialised photoelectron spectroscopy techniques making use of hard x-rays is steadily increasing and ever more complex experimental designs enable truly transformative insights into the chemical, electronic, magnetic, and structural nature of materials. This paper begins with a short historic perspective of HAXPES and spans from developments in the early days of photoelectron spectroscopy to provide an understanding of the origin and initial development of the technique to state-of-the-art instrumentation and experimental capabilities. The main motivation for and focus of this paper is to provide a picture of the technique in 2020, including a detailed overview of available experimental systems worldwide and insights into a range of specific measurement modi and approaches. We also aim to provide a glimpse into the future of the technique including possible developments and opportunities.
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Affiliation(s)
- Curran Kalha
- Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, United Kingdom
| | - Nathalie K Fernando
- Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, United Kingdom
| | - Prajna Bhatt
- Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, United Kingdom
| | - Fredrik O L Johansson
- Department of Physics and Astronomy, Uppsala University, Box 516, 75120 Uppsala, Sweden
| | - Andreas Lindblad
- Department of Physics and Astronomy, Uppsala University, Box 516, 75120 Uppsala, Sweden
| | - Håkan Rensmo
- Department of Physics and Astronomy, Uppsala University, Box 516, 75120 Uppsala, Sweden
| | - León Zendejas Medina
- Department of Chemistry-Ångström Laboratory, Uppsala University, Box 538, SE-75121, Uppsala, Sweden
| | - Rebecka Lindblad
- Department of Chemistry-Ångström Laboratory, Uppsala University, Box 538, SE-75121, Uppsala, Sweden
| | - Sebastian Siol
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Joining Technologies and Corrosion, Dübendorf, Switzerland
| | - Lars P H Jeurgens
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Joining Technologies and Corrosion, Dübendorf, Switzerland
| | - Claudia Cancellieri
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Joining Technologies and Corrosion, Dübendorf, Switzerland
| | - Kai Rossnagel
- Institute of Experimental and Applied Physics, Kiel University, 24098 Kiel, Germany
- Ruprecht Haensel Laboratory, Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | - Katerina Medjanik
- Johannes Gutenberg Universität, Institut für Physik, 55128 Mainz, Germany
| | - Gerd Schönhense
- Johannes Gutenberg Universität, Institut für Physik, 55128 Mainz, Germany
| | - Marc Simon
- Sorbonne Université, CNRS, Laboratoire de Chimie Physique-Matière et Rayonnement, LCPMR, F-75005 Paris, France
| | - Alexander X Gray
- Department of Physics, Temple University, Philadelphia, PA 19122, United States of America
| | - Slavomír Nemšák
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States of America
| | - Patrick Lömker
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | | | - Anna Regoutz
- Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, United Kingdom
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25
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Schönhense G, Kutnyakhov D, Pressacco F, Heber M, Wind N, Agustsson SY, Babenkov S, Vasilyev D, Fedchenko O, Chernov S, Rettig L, Schönhense B, Wenthaus L, Brenner G, Dziarzhytski S, Palutke S, Mahatha SK, Schirmel N, Redlin H, Manschwetus B, Hartl I, Matveyev Y, Gloskovskii A, Schlueter C, Shokeen V, Duerr H, Allison TK, Beye M, Rossnagel K, Elmers HJ, Medjanik K. Suppression of the vacuum space-charge effect in fs-photoemission by a retarding electrostatic front lens. Rev Sci Instrum 2021; 92:053703. [PMID: 34243258 DOI: 10.1063/5.0046567] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 04/04/2021] [Indexed: 06/13/2023]
Abstract
The performance of time-resolved photoemission experiments at fs-pulsed photon sources is ultimately limited by the e-e Coulomb interaction, downgrading energy and momentum resolution. Here, we present an approach to effectively suppress space-charge artifacts in momentum microscopes and photoemission microscopes. A retarding electrostatic field generated by a special objective lens repels slow electrons, retaining the k-image of the fast photoelectrons. The suppression of space-charge effects scales with the ratio of the photoelectron velocities of fast and slow electrons. Fields in the range from -20 to -1100 V/mm for Ekin = 100 eV to 4 keV direct secondaries and pump-induced slow electrons back to the sample surface. Ray tracing simulations reveal that this happens within the first 40 to 3 μm above the sample surface for Ekin = 100 eV to 4 keV. An optimized front-lens design allows switching between the conventional accelerating and the new retarding mode. Time-resolved experiments at Ekin = 107 eV using fs extreme ultraviolet probe pulses from the free-electron laser FLASH reveal that the width of the Fermi edge increases by just 30 meV at an incident pump fluence of 22 mJ/cm2 (retarding field -21 V/mm). For an accelerating field of +2 kV/mm and a pump fluence of only 5 mJ/cm2, it increases by 0.5 eV (pump wavelength 1030 nm). At the given conditions, the suppression mode permits increasing the slow-electron yield by three to four orders of magnitude. The feasibility of the method at high energies is demonstrated without a pump beam at Ekin = 3830 eV using hard x rays from the storage ring PETRA III. The approach opens up a previously inaccessible regime of pump fluences for photoemission experiments.
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Affiliation(s)
- G Schönhense
- Johannes Gutenberg-Universität, Institut für Physik, D-55099 Mainz, Germany
| | - D Kutnyakhov
- Deutsches Elektronen-Synchrotron DESY, D-22607 Hamburg, Germany
| | - F Pressacco
- Deutsches Elektronen-Synchrotron DESY, D-22607 Hamburg, Germany
| | - M Heber
- Deutsches Elektronen-Synchrotron DESY, D-22607 Hamburg, Germany
| | - N Wind
- University of Hamburg, Institut für Experimentalphysik, D-22761 Hamburg, Germany
| | - S Y Agustsson
- Johannes Gutenberg-Universität, Institut für Physik, D-55099 Mainz, Germany
| | - S Babenkov
- Johannes Gutenberg-Universität, Institut für Physik, D-55099 Mainz, Germany
| | - D Vasilyev
- Johannes Gutenberg-Universität, Institut für Physik, D-55099 Mainz, Germany
| | - O Fedchenko
- Johannes Gutenberg-Universität, Institut für Physik, D-55099 Mainz, Germany
| | - S Chernov
- Departments of Chemistry and Physics, Stony Brook University, Stony Brook, New York 11790-3400, USA
| | - L Rettig
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, D-14195 Berlin, Germany
| | - B Schönhense
- Department of Bioengineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - L Wenthaus
- Deutsches Elektronen-Synchrotron DESY, D-22607 Hamburg, Germany
| | - G Brenner
- Deutsches Elektronen-Synchrotron DESY, D-22607 Hamburg, Germany
| | - S Dziarzhytski
- Deutsches Elektronen-Synchrotron DESY, D-22607 Hamburg, Germany
| | - S Palutke
- Deutsches Elektronen-Synchrotron DESY, D-22607 Hamburg, Germany
| | - S K Mahatha
- Ruprecht Haensel Laboratory, Deutsches Elektronen-Synchrotron DESY, D-22607 Hamburg, Germany
| | - N Schirmel
- Deutsches Elektronen-Synchrotron DESY, D-22607 Hamburg, Germany
| | - H Redlin
- Deutsches Elektronen-Synchrotron DESY, D-22607 Hamburg, Germany
| | - B Manschwetus
- Deutsches Elektronen-Synchrotron DESY, D-22607 Hamburg, Germany
| | - I Hartl
- Deutsches Elektronen-Synchrotron DESY, D-22607 Hamburg, Germany
| | - Yu Matveyev
- Deutsches Elektronen-Synchrotron DESY, D-22607 Hamburg, Germany
| | - A Gloskovskii
- Deutsches Elektronen-Synchrotron DESY, D-22607 Hamburg, Germany
| | - C Schlueter
- Deutsches Elektronen-Synchrotron DESY, D-22607 Hamburg, Germany
| | - V Shokeen
- Department of Physics and Astronomy, Uppsala University, P.O. Box 516, 75120 Uppsala, Sweden
| | - H Duerr
- Department of Physics and Astronomy, Uppsala University, P.O. Box 516, 75120 Uppsala, Sweden
| | - T K Allison
- Departments of Chemistry and Physics, Stony Brook University, Stony Brook, New York 11790-3400, USA
| | - M Beye
- Deutsches Elektronen-Synchrotron DESY, D-22607 Hamburg, Germany
| | - K Rossnagel
- Ruprecht Haensel Laboratory, Deutsches Elektronen-Synchrotron DESY, D-22607 Hamburg, Germany
| | - H J Elmers
- Johannes Gutenberg-Universität, Institut für Physik, D-55099 Mainz, Germany
| | - K Medjanik
- Johannes Gutenberg-Universität, Institut für Physik, D-55099 Mainz, Germany
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26
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Agustsson SY, Chernov SV, Medjanik K, Babenkov S, Fedchenko O, Vasilyev D, Schlueter C, Gloskovskii A, Matveyev Y, Kliemt K, Krellner C, Demsar J, Schönhense G, Elmers HJ. Temperature-dependent change of the electronic structure in the Kondo lattice system YbRh 2Si 2. J Phys Condens Matter 2021; 33:205601. [PMID: 33561846 DOI: 10.1088/1361-648x/abe479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 02/09/2021] [Indexed: 06/12/2023]
Abstract
The heavy-fermion behavior in intermetallic compounds manifests itself in a quenching of local magnetic moments by developing Kondo spin-singlet many-body states combined with a drastic increase of the effective mass of conduction electrons, which occurs below the lattice Kondo temperatureTK. This behavior is caused by interactions between the strongly localized 4felectrons and itinerant electrons. A controversially discussed question in this context is how the localized electronic states contribute to the Fermi surface upon changing the temperature. One expects that hybridization between the local moments and the itinerant electrons leads to a transition from a small Fermi surface in a non-coherent regime at high temperatures to a large Fermi surface once the coherent Kondo lattice regime is realized belowTK. We demonstrate, using hard x-ray angle-resolved photoemission spectroscopy that the electronic structure of the prototypical heavy fermion compound YbRh2Si2changes with temperature between 100 and 200 K, i.e. far above the Kondo temperature,TK= 25 K, of this system. Our results suggest a transition from a small to a large Fermi surface with decreasing temperature. This result is inconsistent with the prediction of the dynamical mean-field periodic Anderson model and supports the idea of an independent energy scale governing the change of band dispersion.
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Affiliation(s)
- S Y Agustsson
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, 55128 Mainz, Germany
| | - S V Chernov
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, 55128 Mainz, Germany
| | - K Medjanik
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, 55128 Mainz, Germany
| | - S Babenkov
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, 55128 Mainz, Germany
| | - O Fedchenko
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, 55128 Mainz, Germany
| | - D Vasilyev
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, 55128 Mainz, Germany
| | - C Schlueter
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | - A Gloskovskii
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | - Yu Matveyev
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | - K Kliemt
- Physikalisches Institut, Goethe Universität Frankfurt, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main, Germany
| | - C Krellner
- Physikalisches Institut, Goethe Universität Frankfurt, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main, Germany
| | - J Demsar
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, 55128 Mainz, Germany
| | - G Schönhense
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, 55128 Mainz, Germany
| | - H-J Elmers
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, 55128 Mainz, Germany
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27
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Elmers HJ, Chernov SV, D'Souza SW, Bommanaboyena SP, Bodnar SY, Medjanik K, Babenkov S, Fedchenko O, Vasilyev D, Agustsson SY, Schlueter C, Gloskovskii A, Matveyev Y, Strocov VN, Skourski Y, Šmejkal L, Sinova J, Minár J, Kläui M, Schönhense G, Jourdan M. Néel Vector Induced Manipulation of Valence States in the Collinear Antiferromagnet Mn 2Au. ACS Nano 2020; 14:17554-17564. [PMID: 33236903 DOI: 10.1021/acsnano.0c08215] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The coupling of real and momentum space is utilized to tailor electronic properties of the collinear metallic antiferromagnet Mn2Au by aligning the real space Néel vector indicating the direction of the staggered magnetization. Pulsed magnetic fields of 60 T were used to orient the sublattice magnetizations of capped epitaxial Mn2Au(001) thin films perpendicular to the applied field direction by a spin-flop transition. The electronic structure and its corresponding changes were investigated by angular-resolved photoemission spectroscopy with photon energies in the vacuum-ultraviolet, soft, and hard X-ray range. The results reveal an energetic rearrangement of conduction electrons propagating perpendicular to the Néel vector. They confirm previous predictions on the origin of the Néel spin-orbit torque and anisotropic magnetoresistance in Mn2Au and reflect the combined antiferromagnetic and spin-orbit interaction in this compound leading to inversion symmetry breaking.
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Affiliation(s)
- H J Elmers
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz, Germany
| | - S V Chernov
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz, Germany
| | - S W D'Souza
- New Technologies-Research Centre, University of West Bohemia, Univerzitni 8, 306 14 Pilsen, Czech Republic
| | - S P Bommanaboyena
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz, Germany
| | - S Yu Bodnar
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz, Germany
| | - K Medjanik
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz, Germany
| | - S Babenkov
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz, Germany
| | - O Fedchenko
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz, Germany
| | - D Vasilyev
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz, Germany
| | - S Y Agustsson
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz, Germany
| | - C Schlueter
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | - A Gloskovskii
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | - Yu Matveyev
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | - V N Strocov
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen-PSI, Switzerland
| | - Y Skourski
- Dresden High Magnetic Field Laboratory (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - L Šmejkal
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz, Germany
- Institute of Physics Academy of Sciences of the Czech Republic, Cukrovarnická 10, 162 00 Praha 6, Czech Republic
| | - J Sinova
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz, Germany
- Institute of Physics Academy of Sciences of the Czech Republic, Cukrovarnická 10, 162 00 Praha 6, Czech Republic
| | - J Minár
- New Technologies-Research Centre, University of West Bohemia, Univerzitni 8, 306 14 Pilsen, Czech Republic
| | - M Kläui
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz, Germany
| | - G Schönhense
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz, Germany
| | - M Jourdan
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz, Germany
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28
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Amorese A, Sundermann M, Leedahl B, Marino A, Takegami D, Gretarsson H, Gloskovskii A, Schlueter C, Haverkort MW, Huang Y, Szlawska M, Kaczorowski D, Ran S, Maple MB, Bauer ED, Leithe-Jasper A, Hansmann P, Thalmeier P, Tjeng LH, Severing A. From antiferromagnetic and hidden order to Pauli paramagnetism in U M 2Si 2 compounds with 5 f electron duality. Proc Natl Acad Sci U S A 2020; 117:30220-30227. [PMID: 33203673 PMCID: PMC7720184 DOI: 10.1073/pnas.2005701117] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Using inelastic X-ray scattering beyond the dipole limit and hard X-ray photoelectron spectroscopy we establish the dual nature of the U [Formula: see text] electrons in U[Formula: see text] (M = Pd, Ni, Ru, Fe), regardless of their degree of delocalization. We have observed that the compounds have in common a local atomic-like state that is well described by the U [Formula: see text] configuration with the [Formula: see text] and [Formula: see text] quasi-doublet symmetry. The amount of the U 5[Formula: see text] configuration, however, varies considerably across the U[Formula: see text] series, indicating an increase of U 5f itineracy in going from M = Pd to Ni to Ru and to the Fe compound. The identified electronic states explain the formation of the very large ordered magnetic moments in [Formula: see text] and [Formula: see text], the availability of orbital degrees of freedom needed for the hidden order in [Formula: see text] to occur, as well as the appearance of Pauli paramagnetism in [Formula: see text] A unified and systematic picture of the U[Formula: see text] compounds may now be drawn, thereby providing suggestions for additional experiments to induce hidden order and/or superconductivity in U compounds with the tetragonal body-centered [Formula: see text] structure.
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Affiliation(s)
- Andrea Amorese
- Institute of Physics II, University of Cologne, 50937 Cologne, Germany
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - Martin Sundermann
- Institute of Physics II, University of Cologne, 50937 Cologne, Germany
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - Brett Leedahl
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - Andrea Marino
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - Daisuke Takegami
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - Hlynur Gretarsson
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
- Positron-Elektron-Tandem-Ring-Anlage III (PETRA III), Deutsches Elektronen-Synchrotron, 22607 Hamburg, Germany
| | - Andrei Gloskovskii
- Positron-Elektron-Tandem-Ring-Anlage III (PETRA III), Deutsches Elektronen-Synchrotron, 22607 Hamburg, Germany
| | - Christoph Schlueter
- Positron-Elektron-Tandem-Ring-Anlage III (PETRA III), Deutsches Elektronen-Synchrotron, 22607 Hamburg, Germany
| | - Maurits W Haverkort
- Institute for Theoretical Physics, Heidelberg University, 69120 Heidelberg, Germany
| | - Yingkai Huang
- van der Waals-Zeeman Institute, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Maria Szlawska
- Institute of Low Temperature & Structure Research, Polish Academy of Science, 50-950 Wroclaw, Poland
| | - Dariusz Kaczorowski
- Institute of Low Temperature & Structure Research, Polish Academy of Science, 50-950 Wroclaw, Poland
| | - Sheng Ran
- Department of Physics, University of California San Diego, La Jolla, CA 92093
| | - M Brian Maple
- Department of Physics, University of California San Diego, La Jolla, CA 92093
| | - Eric D Bauer
- MPA-Q, Los Alamos National Laboratory, Los Alamos, NM 87545
| | | | - Philipp Hansmann
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
- Department of Physics, University of Erlangen-Nuremberg, 91058 Erlangen, Germany
| | - Peter Thalmeier
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - Liu Hao Tjeng
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - Andrea Severing
- Institute of Physics II, University of Cologne, 50937 Cologne, Germany;
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
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29
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Paez GJ, Singh CN, Wahila MJ, Tirpak KE, Quackenbush NF, Sallis S, Paik H, Liang Y, Schlom DG, Lee TL, Schlueter C, Lee WC, Piper LFJ. Simultaneous Structural and Electronic Transitions in Epitaxial VO_{2}/TiO_{2}(001). Phys Rev Lett 2020; 124:196402. [PMID: 32469580 DOI: 10.1103/physrevlett.124.196402] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 02/21/2020] [Accepted: 04/21/2020] [Indexed: 06/11/2023]
Abstract
Recent reports have identified new metaphases of VO_{2} with strain and/or doping, suggesting the structural phase transition and the metal-to-insulator transition might be decoupled. Using epitaxially strained VO_{2}/TiO_{2} (001) thin films, which display a bulklike abrupt metal-to-insulator transition and rutile to monoclinic transition structural phase transition, we employ x-ray standing waves combined with hard x-ray photoelectron spectroscopy to simultaneously measure the structural and electronic transitions. This x-ray standing waves study elegantly demonstrates the structural and electronic transitions occur concurrently within experimental limits (±1 K).
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Affiliation(s)
- Galo J Paez
- Department of Physics, Binghamton University, State University of New York, Binghamton, New York 13850, USA
| | - Christopher N Singh
- Department of Physics, Binghamton University, State University of New York, Binghamton, New York 13850, USA
| | - Matthew J Wahila
- Materials Science and Engineering, Binghamton University, State University of New York, Binghamton, New York 13850, USA
| | - Keith E Tirpak
- Department of Physics, Binghamton University, State University of New York, Binghamton, New York 13850, USA
| | - Nicholas F Quackenbush
- Department of Physics, Binghamton University, State University of New York, Binghamton, New York 13850, USA
| | - Shawn Sallis
- Materials Science and Engineering, Binghamton University, State University of New York, Binghamton, New York 13850, USA
| | - Hanjong Paik
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853-1501, USA
- Platform for the Accelerated Realization, Analysis, and Discovery of Interface Materials (PARADIM), Cornell University, Ithaca, New York 14853, USA
| | - Yufeng Liang
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Darrell G Schlom
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853-1501, USA
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853, USA
| | - Tien-Lin Lee
- Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - Christoph Schlueter
- Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - Wei-Cheng Lee
- Department of Physics, Binghamton University, State University of New York, Binghamton, New York 13850, USA
| | - Louis F J Piper
- Department of Physics, Binghamton University, State University of New York, Binghamton, New York 13850, USA
- Materials Science and Engineering, Binghamton University, State University of New York, Binghamton, New York 13850, USA
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30
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Medjanik K, Babenkov SV, Chernov S, Vasilyev D, Schönhense B, Schlueter C, Gloskovskii A, Matveyev Y, Drube W, Elmers HJ, Schönhense G. Progress in HAXPES performance combining full-field k-imaging with time-of-flight recording. J Synchrotron Radiat 2019; 26:1996-2012. [PMID: 31721745 PMCID: PMC6853377 DOI: 10.1107/s1600577519012773] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 09/13/2019] [Indexed: 05/27/2023]
Abstract
An alternative approach to hard-X-ray photoelectron spectroscopy (HAXPES) has been established. The instrumental key feature is an increase of the dimensionality of the recording scheme from 2D to 3D. A high-energy momentum microscope detects electrons with initial kinetic energies up to 8 keV with a k-resolution of 0.025 Å-1, equivalent to an angular resolution of 0.034°. A special objective lens with k-space acceptance up to 25 Å-1 allows for simultaneous full-field imaging of many Brillouin zones. Combined with time-of-flight (ToF) parallel energy recording this yields maximum parallelization. Thanks to the high brilliance (1013 hν s-1 in a spot of <20 µm diameter) of beamline P22 at PETRA III (Hamburg, Germany), the microscope set a benchmark in HAXPES recording speed, i.e. several million counts per second for core-level signals and one million for d-bands of transition metals. The concept of tomographic k-space mapping established using soft X-rays works equally well in the hard X-ray range. Sharp valence band k-patterns of Re, collected at an excitation energy of 6 keV, correspond to direct transitions to the 28th repeated Brillouin zone. Measured total energy resolutions (photon bandwidth plus ToF-resolution) are 62 meV and 180 meV FWHM at 5.977 keV for monochromator crystals Si(333) and Si(311) and 450 meV at 4.0 keV for Si(111). Hard X-ray photoelectron diffraction (hXPD) patterns with rich fine structure are recorded within minutes. The short photoelectron wavelength (10% of the interatomic distance) `amplifies' phase differences, making full-field hXPD a sensitive structural tool.
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Affiliation(s)
- K. Medjanik
- Institut für Physik, Johannes Gutenberg Universität Mainz, D-55099 Mainz, Germany
| | - S. V. Babenkov
- Institut für Physik, Johannes Gutenberg Universität Mainz, D-55099 Mainz, Germany
| | - S. Chernov
- Institut für Physik, Johannes Gutenberg Universität Mainz, D-55099 Mainz, Germany
| | - D. Vasilyev
- Institut für Physik, Johannes Gutenberg Universität Mainz, D-55099 Mainz, Germany
| | - B. Schönhense
- Department of Bioengineering, Imperial College London, UK
| | - C. Schlueter
- DESY Photon Science, Notkestrasse 85, 22607 Hamburg, Germany
| | - A. Gloskovskii
- DESY Photon Science, Notkestrasse 85, 22607 Hamburg, Germany
| | - Yu. Matveyev
- DESY Photon Science, Notkestrasse 85, 22607 Hamburg, Germany
| | - W. Drube
- DESY Photon Science, Notkestrasse 85, 22607 Hamburg, Germany
| | - H. J. Elmers
- Institut für Physik, Johannes Gutenberg Universität Mainz, D-55099 Mainz, Germany
| | - G. Schönhense
- Institut für Physik, Johannes Gutenberg Universität Mainz, D-55099 Mainz, Germany
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31
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Nemšák S, Gehlmann M, Kuo CT, Lin SC, Schlueter C, Mlynczak E, Lee TL, Plucinski L, Ebert H, Di Marco I, Minár J, Schneider CM, Fadley CS. Element- and momentum-resolved electronic structure of the dilute magnetic semiconductor manganese doped gallium arsenide. Nat Commun 2018; 9:3306. [PMID: 30120237 PMCID: PMC6098022 DOI: 10.1038/s41467-018-05823-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2018] [Accepted: 07/23/2018] [Indexed: 11/09/2022] Open
Abstract
The dilute magnetic semiconductors have promise in spin-based electronics applications due to their potential for ferromagnetic order at room temperature, and various unique switching and spin-dependent conductivity properties. However, the precise mechanism by which the transition-metal doping produces ferromagnetism has been controversial. Here we have studied a dilute magnetic semiconductor (5% manganese-doped gallium arsenide) with Bragg-reflection standing-wave hard X-ray angle-resolved photoemission spectroscopy, and resolved its electronic structure into element- and momentum- resolved components. The measured valence band intensities have been projected into element-resolved components using analogous energy scans of Ga 3d, Mn 2p, and As 3d core levels, with results in excellent agreement with element-projected Bloch spectral functions and clarification of the electronic structure of this prototypical material. This technique should be broadly applicable to other multi-element materials.
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Affiliation(s)
- Slavomír Nemšák
- Department of Physics, University of California, 1 Shields Ave, Davis, CA, 95616, USA. .,Materials Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA, 94720, USA. .,Peter-Grünberg-Institut PGI-6, Forschungszentrum Jülich, Jülich, 52425, Germany. .,Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA, 94720, USA.
| | - Mathias Gehlmann
- Department of Physics, University of California, 1 Shields Ave, Davis, CA, 95616, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA, 94720, USA.,Peter-Grünberg-Institut PGI-6, Forschungszentrum Jülich, Jülich, 52425, Germany
| | - Cheng-Tai Kuo
- Department of Physics, University of California, 1 Shields Ave, Davis, CA, 95616, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA, 94720, USA
| | - Shih-Chieh Lin
- Department of Physics, University of California, 1 Shields Ave, Davis, CA, 95616, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA, 94720, USA
| | - Christoph Schlueter
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK.,DESY Photon Science, Deutsches Elektronen-Synchrotron, Hamburg, 22603, Germany
| | - Ewa Mlynczak
- Peter-Grünberg-Institut PGI-6, Forschungszentrum Jülich, Jülich, 52425, Germany
| | - Tien-Lin Lee
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK
| | - Lukasz Plucinski
- Peter-Grünberg-Institut PGI-6, Forschungszentrum Jülich, Jülich, 52425, Germany
| | - Hubert Ebert
- Department of Chemistry, Ludwig Maximillian University, Munich, D-81377, Germany
| | - Igor Di Marco
- Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala, SE, 75120, Sweden.,Asia Pacific Center for Theoretical Physics, Pohang, 37673, Republic of Korea
| | - Ján Minár
- New Technologies-Research Center, University of West Bohemia, Plzen, 306 14, Czech Republic
| | - Claus M Schneider
- Department of Physics, University of California, 1 Shields Ave, Davis, CA, 95616, USA.,Peter-Grünberg-Institut PGI-6, Forschungszentrum Jülich, Jülich, 52425, Germany
| | - Charles S Fadley
- Department of Physics, University of California, 1 Shields Ave, Davis, CA, 95616, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA, 94720, USA
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32
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Schlueter C, Gloskovskii A, Ederer K, Piec S, Sing M, Claessen R, Wiemann C, Schneider C, Medjanik K, Schönhense G, Amann P, Nilsson A, Drube W. New HAXPES Applications at PETRA III. ACTA ACUST UNITED AC 2018. [DOI: 10.1080/08940886.2018.1483656] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- C. Schlueter
- Photon Science, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - A. Gloskovskii
- Photon Science, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - K. Ederer
- Photon Science, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - S. Piec
- Photon Science, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - M. Sing
- Physikalisches Institut and Röntgen Center for Complex Materials Systems, Universität Würzburg, Würzburg, Germany
| | - R. Claessen
- Physikalisches Institut and Röntgen Center for Complex Materials Systems, Universität Würzburg, Würzburg, Germany
| | - C. Wiemann
- Peter Grünberg Institut, Jülich, Germany
| | | | - K. Medjanik
- Institut für Physik, Johannes Gutenberg-Universität, Mainz, Germany
| | - G. Schönhense
- Institut für Physik, Johannes Gutenberg-Universität, Mainz, Germany
| | - P. Amann
- Department of Physics, AlbaNova University Center, Stockholm University, Stockholm, Sweden
| | - A. Nilsson
- Department of Physics, AlbaNova University Center, Stockholm University, Stockholm, Sweden
| | - W. Drube
- Photon Science, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
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33
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Scheiderer P, Schmitt M, Gabel J, Zapf M, Stübinger M, Schütz P, Dudy L, Schlueter C, Lee TL, Sing M, Claessen R. Tailoring Materials for Mottronics: Excess Oxygen Doping of a Prototypical Mott Insulator. Adv Mater 2018; 30:e1706708. [PMID: 29732633 DOI: 10.1002/adma.201706708] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 02/02/2018] [Indexed: 06/08/2023]
Abstract
The Mott transistor is a paradigm for a new class of electronic devices-often referred to by the term Mottronics-which are based on charge correlations between the electrons. Since correlation-induced insulating phases of most oxide compounds are usually very robust, new methods have to be developed to push such materials right to the boundary to the metallic phase in order to enable the metal-insulator transition to be switched by electric gating. Here, it is demonstrated that thin films of the prototypical Mott insulator LaTiO3 grown by pulsed laser deposition under oxygen atmosphere are readily tuned by excess oxygen doping across the line of the band-filling controlled Mott transition in the electronic phase diagram. The detected insulator to metal transition is characterized by a strong change in resistivity of several orders of magnitude. The use of suitable substrates and capping layers to inhibit oxygen diffusion facilitates full control of the oxygen content and renders the films stable against exposure to ambient conditions. These achievements represent a significant advancement in control and tuning of the electronic properties of LaTiO3+x thin films making it a promising channel material in future Mottronic devices.
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Affiliation(s)
- Philipp Scheiderer
- Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, Am Hubland, D-97074, Würzburg, Germany
| | - Matthias Schmitt
- Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, Am Hubland, D-97074, Würzburg, Germany
| | - Judith Gabel
- Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, Am Hubland, D-97074, Würzburg, Germany
| | - Michael Zapf
- Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, Am Hubland, D-97074, Würzburg, Germany
| | - Martin Stübinger
- Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, Am Hubland, D-97074, Würzburg, Germany
| | - Philipp Schütz
- Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, Am Hubland, D-97074, Würzburg, Germany
| | - Lenart Dudy
- Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, Am Hubland, D-97074, Würzburg, Germany
| | | | - Tien-Lin Lee
- Diamond Light Source Ltd., Didcot, Oxfordshire, OX11 0DE, UK
| | - Michael Sing
- Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, Am Hubland, D-97074, Würzburg, Germany
| | - Ralph Claessen
- Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, Am Hubland, D-97074, Würzburg, Germany
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34
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Pincelli T, Lollobrigida V, Borgatti F, Regoutz A, Gobaut B, Schlueter C, Lee TL, Payne DJ, Oura M, Tamasaku K, Petrov AY, Graziosi P, Granozio FM, Cavallini M, Vinai G, Ciprian R, Back CH, Rossi G, Taguchi M, Daimon H, van der Laan G, Panaccione G. Quantifying the critical thickness of electron hybridization in spintronics materials. Nat Commun 2017; 8:16051. [PMID: 28714466 PMCID: PMC5520016 DOI: 10.1038/ncomms16051] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 05/15/2017] [Indexed: 11/09/2022] Open
Abstract
In the rapidly growing field of spintronics, simultaneous control of electronic and magnetic properties is essential, and the perspective of building novel phases is directly linked to the control of tuning parameters, for example, thickness and doping. Looking at the relevant effects in interface-driven spintronics, the reduced symmetry at a surface and interface corresponds to a severe modification of the overlap of electron orbitals, that is, to a change of electron hybridization. Here we report a chemically and magnetically sensitive depth-dependent analysis of two paradigmatic systems, namely La1−xSrxMnO3 and (Ga,Mn)As. Supported by cluster calculations, we find a crossover between surface and bulk in the electron hybridization/correlation and we identify a spectroscopic fingerprint of bulk metallic character and ferromagnetism versus depth. The critical thickness and the gradient of hybridization are measured, setting an intrinsic limit of 3 and 10 unit cells from the surface, respectively, for (Ga,Mn)As and La1−xSrxMnO3, for fully restoring bulk properties. Surface versus bulk effects in electronic structure of spintronics materials are crucial to their applications but are yet well understood. Here the authors experimentally determine the critical thickness that defines the crossover of electron hybridization between surface and bulk for two prototype spintronics materials.
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Affiliation(s)
- T Pincelli
- Istituto Officina dei Materiali-CNR, Laboratorio TASC, Area Science Park, S.S. 14, Km 163.5, Trieste I-34149, Italy.,Dipartimento di Fisica, Università di Milano, Via Celoria 16, Milano I-20133, Italy
| | - V Lollobrigida
- Istituto Officina dei Materiali-CNR, Laboratorio TASC, Area Science Park, S.S. 14, Km 163.5, Trieste I-34149, Italy.,Dipartimento di Scienze, Università degli Studi Roma Tre, Via della Vasca Navale 84, Roma I-00146, Italy
| | - F Borgatti
- Consiglio Nazionale delle Ricerche-Istituto per lo Studio dei Materiali Nanostrutturati (CNR-ISMN), via P. Gobetti 101, Bologna I-40129, Italy
| | - A Regoutz
- Department of Materials, Imperial College London, South Kensington, London SW7 2AZ, UK
| | - B Gobaut
- Sincrotrone Trieste S.C.p.A., S.S. 14 Km 163.5, Area Science Park, Trieste 34149, Italy
| | - C Schlueter
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK
| | - T-L Lee
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK
| | - D J Payne
- Department of Materials, Imperial College London, South Kensington, London SW7 2AZ, UK
| | - M Oura
- RIKEN SPring-8 Center, Kouto 1-1-1, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - K Tamasaku
- RIKEN SPring-8 Center, Kouto 1-1-1, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - A Y Petrov
- Istituto Officina dei Materiali-CNR, Laboratorio TASC, Area Science Park, S.S. 14, Km 163.5, Trieste I-34149, Italy
| | - P Graziosi
- Consiglio Nazionale delle Ricerche-Istituto per lo Studio dei Materiali Nanostrutturati (CNR-ISMN), via P. Gobetti 101, Bologna I-40129, Italy
| | - F Miletto Granozio
- CNR-SPIN, Complesso Universitario Monte S. Angelo, Napoli 80126, Italy.,Dipartimento di Fisica, Università 'Federico II' di Napoli, Napoli, 80126, Italy
| | - M Cavallini
- Consiglio Nazionale delle Ricerche-Istituto per lo Studio dei Materiali Nanostrutturati (CNR-ISMN), via P. Gobetti 101, Bologna I-40129, Italy
| | - G Vinai
- Istituto Officina dei Materiali-CNR, Laboratorio TASC, Area Science Park, S.S. 14, Km 163.5, Trieste I-34149, Italy
| | - R Ciprian
- Istituto Officina dei Materiali-CNR, Laboratorio TASC, Area Science Park, S.S. 14, Km 163.5, Trieste I-34149, Italy
| | - C H Back
- Institut fur Experimentelle Physik, Universitat Regensburg, Regensburg D-93040, Germany
| | - G Rossi
- Istituto Officina dei Materiali-CNR, Laboratorio TASC, Area Science Park, S.S. 14, Km 163.5, Trieste I-34149, Italy.,Dipartimento di Fisica, Università di Milano, Via Celoria 16, Milano I-20133, Italy
| | - M Taguchi
- RIKEN SPring-8 Center, Kouto 1-1-1, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan.,Nara Institute of Science and Technology, 8-9165 Takayama, Ikoma, Nara 630-0192, Japan
| | - H Daimon
- Nara Institute of Science and Technology, 8-9165 Takayama, Ikoma, Nara 630-0192, Japan
| | - G van der Laan
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK
| | - G Panaccione
- Istituto Officina dei Materiali-CNR, Laboratorio TASC, Area Science Park, S.S. 14, Km 163.5, Trieste I-34149, Italy
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35
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Farwick Zum Hagen FH, Zimmermann DM, Silva CC, Schlueter C, Atodiresei N, Jolie W, Martínez-Galera AJ, Dombrowski D, Schröder UA, Will M, Lazić P, Caciuc V, Blügel S, Lee TL, Michely T, Busse C. Structure and Growth of Hexagonal Boron Nitride on Ir(111). ACS Nano 2016; 10:11012-11026. [PMID: 28024332 DOI: 10.1021/acsnano.6b05819] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Using the X-ray standing wave method, scanning tunneling microscopy, low energy electron diffraction, and density functional theory, we precisely determine the lateral and vertical structure of hexagonal boron nitride on Ir(111). The moiré superstructure leads to a periodic arrangement of strongly chemisorbed valleys in an otherwise rather flat, weakly physisorbed plane. The best commensurate approximation of the moiré unit cell is (12 × 12) boron nitride cells resting on (11 × 11) substrate cells, which is at variance with several earlier studies. We uncover the existence of two fundamentally different mechanisms of layer formation for hexagonal boron nitride, namely, nucleation and growth as opposed to network formation without nucleation. The different pathways are linked to different distributions of rotational domains, and the latter enables selection of a single orientation only.
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Affiliation(s)
| | - Domenik M Zimmermann
- II. Physikalisches Institut, Universität zu Köln , Zülpicher Straße 77, 50937 Köln, Germany
| | - Caio C Silva
- II. Physikalisches Institut, Universität zu Köln , Zülpicher Straße 77, 50937 Köln, Germany
- Institut für Materialphysik, Westfälische Wilhelms-Universität Münster , Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
| | | | - Nicolae Atodiresei
- Peter Grünberg Institut (PGI) and Institute for Advanced Simulation (IAS), Forschungszentrum Jülich and JARA , 52425 Jülich, Germany
| | - Wouter Jolie
- II. Physikalisches Institut, Universität zu Köln , Zülpicher Straße 77, 50937 Köln, Germany
| | | | - Daniela Dombrowski
- II. Physikalisches Institut, Universität zu Köln , Zülpicher Straße 77, 50937 Köln, Germany
- Institut für Materialphysik, Westfälische Wilhelms-Universität Münster , Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
| | - Ulrike A Schröder
- II. Physikalisches Institut, Universität zu Köln , Zülpicher Straße 77, 50937 Köln, Germany
| | - Moritz Will
- II. Physikalisches Institut, Universität zu Köln , Zülpicher Straße 77, 50937 Köln, Germany
| | - Predrag Lazić
- Institut Ruđer Bošković , Bijenička 54, 10000 Zagreb, Croatia
| | - Vasile Caciuc
- Peter Grünberg Institut (PGI) and Institute for Advanced Simulation (IAS), Forschungszentrum Jülich and JARA , 52425 Jülich, Germany
| | - Stefan Blügel
- Peter Grünberg Institut (PGI) and Institute for Advanced Simulation (IAS), Forschungszentrum Jülich and JARA , 52425 Jülich, Germany
| | | | - Thomas Michely
- II. Physikalisches Institut, Universität zu Köln , Zülpicher Straße 77, 50937 Köln, Germany
| | - Carsten Busse
- II. Physikalisches Institut, Universität zu Köln , Zülpicher Straße 77, 50937 Köln, Germany
- Institut für Materialphysik, Westfälische Wilhelms-Universität Münster , Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
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36
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Dudy L, Sing M, Scheiderer P, Denlinger JD, Schütz P, Gabel J, Buchwald M, Schlueter C, Lee TL, Claessen R. In Situ Control of Separate Electronic Phases on SrTiO3 Surfaces by Oxygen Dosing. Adv Mater 2016; 28:7443-7449. [PMID: 27332795 DOI: 10.1002/adma.201600046] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 05/10/2016] [Indexed: 06/06/2023]
Abstract
Insulating SrTiO3 (STO) can host 2D electron systems (2DESs) on its surfaces, caused by oxygen defects. This study shows that the STO surface exhibits phase separation once the 2DES is formed and relates this inhomogeneity to recently reported magnetic order at STO surfaces and interfaces. The results open pathways to exploit oxygen defects for engineering the electronic and magnetic properties of oxides.
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Affiliation(s)
- Lenart Dudy
- Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, D-97074, Würzburg, Germany.
| | - Michael Sing
- Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, D-97074, Würzburg, Germany
| | - Philipp Scheiderer
- Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, D-97074, Würzburg, Germany
| | - Jonathan D Denlinger
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94270, USA
| | - Philipp Schütz
- Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, D-97074, Würzburg, Germany
| | - Judith Gabel
- Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, D-97074, Würzburg, Germany
| | - Mathias Buchwald
- Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, D-97074, Würzburg, Germany
| | | | - Tien-Lin Lee
- Diamond Light Source Ltd, Didcot, Oxfordshire, OX11 0DE, UK
| | - Ralph Claessen
- Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, D-97074, Würzburg, Germany
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37
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Wojciechowski K, Leijtens T, Siprova S, Schlueter C, Hörantner MT, Wang JTW, Li CZ, Jen AKY, Lee TL, Snaith HJ. C60 as an Efficient n-Type Compact Layer in Perovskite Solar Cells. J Phys Chem Lett 2015; 6:2399-405. [PMID: 26266623 DOI: 10.1021/acs.jpclett.5b00902] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Organic-inorganic halide perovskite solar cells have rapidly evolved over the last 3 years. There are still a number of issues and open questions related to the perovskite material, such as the phenomenon of anomalous hysteresis in current-voltage characteristics and long-term stability of the devices. In this work, we focus on the electron selective contact in the perovskite solar cells and physical processes occurring at that heterojunction. We developed efficient devices by replacing the commonly employed TiO2 compact layer with fullerene C60 in a regular n-i-p architecture. Detailed spectroscopic characterization allows us to present further insight into the nature of photocurrent hysteresis and charge extraction limitations arising at the n-type contact in a standard device. Furthermore, we show preliminary stability data of perovskite solar cells under working conditions, suggesting that an n-type organic charge collection layer can increase the long-term performance.
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Affiliation(s)
- Konrad Wojciechowski
- †Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom
| | - Tomas Leijtens
- †Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom
- ‡Center for Nano Science and Technology@Polimi, Istituto Italiano di Tecnologia, via Giovanni Pascoli 70/3, 20133, Milan, Italy
| | - Svetlana Siprova
- †Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom
- §Dipartimento di Fisica, Università della Calabria, via Bucci, Rende, 87036, Italy
| | | | - Maximilian T Hörantner
- †Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom
| | - Jacob Tse-Wei Wang
- †Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom
| | | | | | | | - Henry J Snaith
- †Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom
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38
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Yang N, Belianinov A, Strelcov E, Tebano A, Foglietti V, Di Castro D, Schlueter C, Lee TL, Baddorf AP, Balke N, Jesse S, Kalinin SV, Balestrino G, Aruta C. Effect of doping on surface reactivity and conduction mechanism in samarium-doped ceria thin films. ACS Nano 2014; 8:12494-12501. [PMID: 25415828 DOI: 10.1021/nn505345c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A systematic study by reversible and hysteretic electrochemical strain microscopy (ESM) in samples of cerium oxide with different Sm content and in several working conditions allows disclosing the microscopic mechanism underlying the difference in electrical conduction mechanism and related surface activity, such as water adsorption and dissociation with subsequent proton liberation. We have measured the behavior of the reversible hysteresis loops by changing temperature and humidity, both in standard ESM configuration and using the first-order reversal curve method. The measurements have been performed in much smaller temperature ranges with respect to alternative measuring techniques. Complementing our study with hard X-ray photoemission spectroscopy and irreversible scanning probe measurements, we find that water incorporation is favored until the doping with Sm is too high to allow the presence of Ce3+. The influence of doping on the surface reactivity clearly emerges from all of our experimental results. We find that at lower Sm concentration, proton conduction is prevalent, featured by lower activation energy and higher electrical conductivity. Defect concentrations determine the type of the prevalent charge carrier in a doping dependent manner.
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Affiliation(s)
- Nan Yang
- National Research Council CNR-SPIN, University of Roma "Tor Vergata" , Rome I-00133, Italy
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39
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Meyerheim HL, Ernst A, Mohseni K, Maznichenko IV, Henk J, Ostanin S, Jedrecy N, Klimenta F, Zegenhagen J, Schlueter C, Mertig I, Kirschner J. Tuning the structure of ultrathin BaTiO3 films on Me(001) (Me=Fe, Pd, Pt) surfaces. Phys Rev Lett 2013; 111:105501. [PMID: 25166678 DOI: 10.1103/physrevlett.111.105501] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2012] [Revised: 03/01/2013] [Indexed: 06/03/2023]
Abstract
Using surface x-ray diffraction in combination with ab initio calculations, we demonstrate that the atomic structure of ultrathin BaTiO3 (BTO) films grown on Me(001) surfaces (Me=Fe, Pd, Pt) depends on subtle modifications of the interface chemical composition. A complete reversal of the surface termination from a BaO- [BTO on Fe(001)] to a TiO2-terminated film [BTO on Pt(001)] is observed which goes in parallel with the adsorption of submonolayer amounts of oxygen at metal hollow sites of the interface. Our results may suggest a new route to an overall control of both the surface and the interface geometry in BaTiO3/metal contacts.
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Affiliation(s)
- H L Meyerheim
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
| | - A Ernst
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany and Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linnéstraße 2, 04103 Leipzig, Germany
| | - K Mohseni
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
| | - I V Maznichenko
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, D-06099 Halle, Germany
| | - J Henk
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, D-06099 Halle, Germany
| | - S Ostanin
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
| | - N Jedrecy
- Institut des Nano Sciences de Paris, UPMC-Sorbonne Universités, CNRS-UMR7588, 75005 Paris, France
| | - F Klimenta
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
| | - J Zegenhagen
- ESRF, Boîte Postale 220, F-38043 Grenoble Cedex, France
| | - C Schlueter
- ESRF, Boîte Postale 220, F-38043 Grenoble Cedex, France
| | - I Mertig
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany and Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, D-06099 Halle, Germany
| | - J Kirschner
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany and Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, D-06099 Halle, Germany
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40
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Affiliation(s)
- S Batni
- Neuroscience Research Institute, University of California, Santa Barbara 93117, USA
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41
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Abstract
The photoreceptors of the vertebrate retina express a large number of proteins that are involved in the process of light transduction. These genes appear to be coordinately regulated at the level of transcription, with rod- and cone-specific isoforms (J. Hurley (1992) J. Bioenerg. Biomembr. 24, 219-226). The mechanisms that regulate gene expression in a rod/cone-specific fashion have been difficult to address using traditional approaches and remain unknown. Regulation of the phototransduction proteins is medically important, since mutations in several of them cause retinal degeneration (P. Rosenfeld and T. Dryja (1995) in: Molecular Genetics of Ocular Disease (J.L. Wiggs, Ed.), pp. 99-126, Wiley-Liss Inc.). An experimental system for rapidly producing retinas expressing a desired mutant would greatly facilitate investigations of retinal degeneration. We report here that transgenic frog embryos (K. Kroll and E. Amaya (1996) Development 122, 3173-3183) can be used to study cell-specific expression in the retina. We have used a 5.5 kb 5' upstream fragment from the Xenopus principal rod opsin gene (S. Batni et al. (1996) J. Biol. Chem. 271, 3179-3186) controlling a reporter gene, green fluorescent protein (GFP), to produce numerous independent transgenic Xenopus. We find that this construct drives expression only in the retina and pineal, which is apparent by 4 days post-nuclear injection. These are the first results using transgenic Xenopus for retinal promoter analysis and the potential for the expression in rod photoreceptors of proteins with dominant phenotypes.
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Affiliation(s)
- B E Knox
- Department of Biochemistry and Molecular Biology, SUNY Health Science Center at Syracuse, NY 13210, USA.
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42
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Hawrylak N, Ghosh P, Broadus J, Schlueter C, Greenough WT, Lauterbur PC. Nuclear magnetic resonance (NMR) imaging of iron oxide-labeled neural transplants. Exp Neurol 1993; 121:181-92. [PMID: 8339769 DOI: 10.1006/exnr.1993.1085] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Nuclear magnetic resonance (NMR) imaging in vivo of adult rat brains was used to observe the fate of iron oxide-labeled intracerebral neural grafts. The host animals received grafts of fetal (E17-E18) rat tissue prepared as cell suspensions and labeled by incubation with reconstituted Sendai viral envelopes containing iron oxide particles. Control studies were performed in animals following surgical trauma alone or transplantation of unlabeled cell suspensions. In vivo NMR imaging (either two-dimensional Fourier transform or three-dimensional Fourier transform) was performed once on each animal between 5 and 60 days postsurgery. The NMR images of the host brains containing the labeled cells showed sufficient anatomical detail for the identification of the major brain structures. The graft sites were seen in the T2-weighted NMR images as dark regions (low-intensity signal) in the cortex. Histochemical staining for ferric iron (prussian blue stain) demonstrated the presence of numerous prussian blue-positive cells in tissue sections corresponding to the dark regions in the NMR images. Surviving prussian blue-positive cells with neuron-like morphology were relatively more numerous 10 days after transplantation than at 1-2 months postgrafting. The NMR images and immunohistochemical and histochemical staining of hosts containing labeled cells suggest cell migration of astrocytes and macrophages up to 2 mm away from the graft sites. The migrating cells were primarily along fiber tracts in the host white matter. Prussian blue deposits were also present within the brains of the control animals, but the NMR images from the same animals did not contain distinct dark regions like those in the images of brains which had received labeled cell transplants. These results demonstrate that NMR imaging can be used to study cell survival and migration following neural grafting procedures.
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Affiliation(s)
- N Hawrylak
- Beckman Institute, University of Illinois, Urbana, Champaign 61801
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43
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Gerdes J, Li L, Schlueter C, Duchrow M, Wohlenberg C, Gerlach C, Stahmer I, Kloth S, Brandt E, Flad HD. Immunobiochemical and molecular biologic characterization of the cell proliferation-associated nuclear antigen that is defined by monoclonal antibody Ki-67. Am J Pathol 1991; 138:867-73. [PMID: 2012175 PMCID: PMC1886092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The monoclonal antibody Ki-67 detects a human nuclear antigen that is present in proliferating cells, but absent in quiescent cells. The aim of this study was to characterize the Ki-67 antigen by means of immunobiochemical and molecular biology techniques. Enzymatic digestion experiments showed that this antigen is highly susceptible to protease treatment, and the antigen cannot be extracted by 0.1 normal HCl, indicating that Ki-67 antigen is a nonhistone protein. Immunoblot analysis of cell lysates with Ki-67 showed a double band with apparent molecular weights of 395 kd and 345 kd, regardless of whether the gels were run under reducing or nonreducing conditions. It is noteworthy that these bands were exclusively detectable in lysates prepared from proliferating cells, whereas they were absent in lysates obtained from quiescent cells. These immunobiochemical data are further substantiated by our molecular cloning approaches. By means of immunocloning with Ki-67, the authors isolated and sequenced several cDNA fragments from lambda gt11 libraries. A 1095-bp fragment gave a strong hybridization signal at 7.5 to 9.5 kb in Northern blot analysis with RNA prepared from proliferating cells, whereas it was negative with RNA prepared from quiescent cells. This cDNA fragment could be bacterially expressed, and in subsequent immunoblot analysis Ki-67 reacted exclusively with those fusion proteins that were derived from bacteria containing the insert in the right reading frame.
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Affiliation(s)
- J Gerdes
- Division of Molecular Immunology, Forschungsinstitut Borstel, Federal Republic of Germany
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