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Dehn MH, Cao Y, Wang PX, Cottrell SP, MacLachlan MJ, Fleming DG, Kiefl RF. Direct observation of muonium reacting with uncapped gold nanoparticles in porous silica and nature of the final state. J Chem Phys 2020; 152:184706. [PMID: 32414252 DOI: 10.1063/5.0004210] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We report the reaction of muonium (Mu = [μ+e-]), a light isotopic analog of hydrogen, with uncapped gold nanoparticles embedded in mesoporous silica. Using the radio-frequency muon spin rotation (RF-μSR) technique, we directly observe and characterize the resulting final state on the nanoparticle surface, showing conclusively its diamagnetic nature. The magnetic environment experienced by the reacted muons is only weakly perturbed compared to that of muons in a silica reference, consistent with the surface of the gold nanoparticles being metallic and non-magnetic. We demonstrate the potential of RF-μSR for the investigation of the surface properties of nanoparticles and show the feasibility of Knight shift measurements of muons on metal surfaces.
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Affiliation(s)
- M H Dehn
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Y Cao
- Stewart Blusson Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - P-X Wang
- Stewart Blusson Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - S P Cottrell
- ISIS Facility, Rutherford Appleton Laboratory, Harwell Campus, Didcot, Oxon OX11 0QX, United Kingdom
| | - M J MacLachlan
- Stewart Blusson Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - D G Fleming
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
| | - R F Kiefl
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
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Lord JS, McKenzie I, Baker PJ, Blundell SJ, Cottrell SP, Giblin SR, Good J, Hillier AD, Holsman BH, King PJC, Lancaster T, Mitchell R, Nightingale JB, Owczarkowski M, Poli S, Pratt FL, Rhodes NJ, Scheuermann R, Salman Z. Design and commissioning of a high magnetic field muon spin relaxation spectrometer at the ISIS pulsed neutron and muon source. Rev Sci Instrum 2011; 82:073904. [PMID: 21806196 DOI: 10.1063/1.3608114] [Citation(s) in RCA: 5] [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] [Indexed: 05/31/2023]
Abstract
The high magnetic field (HiFi) muon instrument at the ISIS pulsed neutron and muon source is a state-of-the-art spectrometer designed to provide applied magnetic fields up to 5 T for muon studies of condensed matter and molecular systems. The spectrometer is optimised for time-differential muon spin relaxation studies at a pulsed muon source. We describe the challenges involved in its design and construction, detailing, in particular, the magnet and detector performance. Commissioning experiments have been conducted and the results are presented to demonstrate the scientific capabilities of the new instrument.
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Affiliation(s)
- J S Lord
- ISIS Facility, STFC Rutherford Appleton Laboratory, Chilton, Oxon OX11 0QX, United Kingdom
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Eshchenko DG, Storchak VG, Cottrell SP, Morenzoni E. Electric-field-enhanced neutralization of deep centers in GaAs. Phys Rev Lett 2009; 103:216601. [PMID: 20366057 DOI: 10.1103/physrevlett.103.216601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2009] [Indexed: 05/29/2023]
Abstract
The charge dynamics of hydrogenlike centers in semi-insulating GaAs have been studied by muon spin resonance in the presence of electric field and RF excitation. Electric-field-enhanced neutralization of deep electron and hole traps by track-induced hot carriers results in an increase of the excess electron's or hole's lifetimes. Similar processes may take place in semiconductor devices working at high voltages and/or under irradiation. As a consequence of the deep traps neutralization, the muonium (mu{+} + e{-}) center can capture a hole.
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Affiliation(s)
- D G Eshchenko
- Physik-Institut der Universität Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland.
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Mansour AI, Salman Z, Chow KH, Fan I, King PJC, Hitti B, Jung J, Cottrell SP. Dynamics and reactivity of positively charged muonium in heavily doped Si:B and comparisons with hydrogen. Phys Rev Lett 2008; 100:257602. [PMID: 18643703 DOI: 10.1103/physrevlett.100.257602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2007] [Indexed: 05/26/2023]
Abstract
The detailed dynamics of the positively charged muonium (Mu+) in heavily doped p-type Si:B is reported. Below 200 K, Mu+ is static and isolated, and is located in a stretched Si-Si bond. Above approximately 200 K, Mu+ diffuses incoherently. At temperatures higher than 300 K, the Mu+-B- complex is formed while above 520 K, it starts to dissociate. There is significant enhancement of the diffusion of Mu+ in Si compared to H+ and D+-this is attributed to its smaller mass.
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Affiliation(s)
- A I Mansour
- Department of Physics, University of Alberta, Edmonton, Alberta, Canada T6G 2G7.
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Yaouanc A, de Réotier PD, Gubbens PCM, Kaiser CT, Menovsky AA, Mihalik M, Cottrell SP. Evidence for weak itinerant long-range magnetic correlations in UGe2. Phys Rev Lett 2002; 89:147001. [PMID: 12366066 DOI: 10.1103/physrevlett.89.147001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2001] [Indexed: 05/23/2023]
Abstract
Positive muon spin relaxation measurements performed on the ferromagnet UGe2 reveal, in addition to the well-known localized 5f-electron density responsible for the bulk magnetic properties, the existence of itinerant quasistatic magnetic correlations. Their critical dynamics is well described by the conventional dipolar Heisenberg model. These correlations involve small magnetic moments.
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Affiliation(s)
- A Yaouanc
- Commissariat à l'Energie Atomique, Département de Recherche Fondamentale sur la Matière Condensée, F-38054 Grenoble Cedex 9, France
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Cox SF, Davis EA, Cottrell SP, King PJ, Lord JS, Gil JM, Alberto HV, Vilão RC, Piroto Duarte J, Ayres de Campos N, Weidinger A, Lichti RL, Irvine SJ. Experimental confirmation of the predicted shallow donor hydrogen state in zinc oxide. Phys Rev Lett 2001; 86:2601-4. [PMID: 11289990 DOI: 10.1103/physrevlett.86.2601] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2000] [Indexed: 05/20/2023]
Abstract
We confirm the recent prediction that interstitial protium may act as a shallow donor in zinc oxide, by direct spectroscopic observation of its muonium counterpart. On implantation into ZnO, positive muons--chemically analogous to protons in this context--form paramagnetic centers below about 40 K. The muon-electron contact hyperfine interaction, as well as the temperature and activation energy for ionization, imply a shallow level. Similar results for the cadmium chalcogenides suggest that such shallow donor states are generic to the II-VI compounds. The donor level depths should serve as a guide for the electrical activity of interstitial hydrogen.
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Affiliation(s)
- S F Cox
- ISIS Facility, Rutherford Appleton Laboratory, Chilton OX11 0QX, UK
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Storchak VG, Eshchenko DG, Brewer JH, Morris GD, Cottrell SP, Cox SF. Electron localization in a disordered insulating host. Phys Rev Lett 2000; 85:166-169. [PMID: 10991185 DOI: 10.1103/physrevlett.85.166] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2000] [Indexed: 05/23/2023]
Abstract
Transport of excess electrons has been studied in solid N2-Ar mixtures between 5 and 60 K using muon spin rotation in magnetic and electric fields. At low temperatures, orientational frustration of N2 molecular quadrupoles by a sufficiently high concentration of Ar atoms leads to formation of a quadrupolar glass phase in which electrons are found to be strongly localized. This feature is in marked contrast to the electron delocalization observed in the low-temperature alpha phase of pure solid nitrogen, which shows long-range orientational order.
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Affiliation(s)
- VG Storchak
- Russian Research Centre "Kurchatov Institute," Kurchatov Square 46, Moscow 123182, Russia
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Storchak V, Cox SF, Cottrell SP, Brewer JH, Morris GD, Prokof'ev NV. Muonium localization in solid krypton. Phys Rev B Condens Matter 1996; 53:662-667. [PMID: 9983017 DOI: 10.1103/physrevb.53.662] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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