1
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Carey B, Wessling NK, Steeger P, Schmidt R, Michaelis de Vasconcellos S, Bratschitsch R, Arora A. Giant Faraday rotation in atomically thin semiconductors. Nat Commun 2024; 15:3082. [PMID: 38600090 PMCID: PMC11006678 DOI: 10.1038/s41467-024-47294-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 03/21/2024] [Indexed: 04/12/2024] Open
Abstract
Faraday rotation is a fundamental effect in the magneto-optical response of solids, liquids and gases. Materials with a large Verdet constant find applications in optical modulators, sensors and non-reciprocal devices, such as optical isolators. Here, we demonstrate that the plane of polarization of light exhibits a giant Faraday rotation of several degrees around the A exciton transition in hBN-encapsulated monolayers of WSe2 and MoSe2 under moderate magnetic fields. This results in the highest known Verdet constant of -1.9 × 107 deg T-1 cm-1 for any material in the visible regime. Additionally, interlayer excitons in hBN-encapsulated bilayer MoS2 exhibit a large Verdet constant (VIL ≈ +2 × 105 deg T-1 cm-2) of opposite sign compared to A excitons in monolayers. The giant Faraday rotation is due to the giant oscillator strength and high g-factor of the excitons in atomically thin semiconducting transition metal dichalcogenides. We deduce the complete in-plane complex dielectric tensor of hBN-encapsulated WSe2 and MoSe2 monolayers, which is vital for the prediction of Kerr, Faraday and magneto-circular dichroism spectra of 2D heterostructures. Our results pose a crucial advance in the potential usage of two-dimensional materials in ultrathin optical polarization devices.
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Affiliation(s)
- Benjamin Carey
- Institute of Physics and Center for Nanotechnology, University of Münster, Wilhelm-Klemm-Strasse 10, Münster, Germany
- School of Mathematics and Physics, The University of Queensland, St Lucia, QLD, Australia
| | - Nils Kolja Wessling
- Institute of Physics and Center for Nanotechnology, University of Münster, Wilhelm-Klemm-Strasse 10, Münster, Germany
- Institute of Photonics, Department of Physics, University of Strathclyde, 99 George Street, Glasgow, UK
| | - Paul Steeger
- Institute of Physics and Center for Nanotechnology, University of Münster, Wilhelm-Klemm-Strasse 10, Münster, Germany
| | - Robert Schmidt
- Institute of Physics and Center for Nanotechnology, University of Münster, Wilhelm-Klemm-Strasse 10, Münster, Germany
| | | | - Rudolf Bratschitsch
- Institute of Physics and Center for Nanotechnology, University of Münster, Wilhelm-Klemm-Strasse 10, Münster, Germany.
| | - Ashish Arora
- Institute of Physics and Center for Nanotechnology, University of Münster, Wilhelm-Klemm-Strasse 10, Münster, Germany.
- Department of Physics, Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pune, Maharashtra, India.
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2
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Tran TT, Lee Y, Roy S, Tran TU, Kim Y, Taniguchi T, Watanabe K, Milošević MV, Lim SC, Chaves A, Jang JI, Kim J. Synergetic Enhancement of Quantum Yield and Exciton Lifetime of Monolayer WS 2 by Proximal Metal Plate and Negative Electric Bias. ACS NANO 2024; 18:220-228. [PMID: 38127273 DOI: 10.1021/acsnano.3c05667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
The efficiency of light emission is a critical performance factor for monolayer transition metal dichalcogenides (1L-TMDs) for photonic applications. While various methods have been studied to compensate for lattice defects to improve the quantum yield (QY) of 1L-TMDs, exciton-exciton annihilation (EEA) is still a major nonradiative decay channel for excitons at high exciton densities. Here, we demonstrate that the combined use of a proximal Au plate and a negative electric gate bias (NEGB) for 1L-WS2 provides a dramatic enhancement of the exciton lifetime at high exciton densities with the corresponding QY enhanced by 30 times and the EEA rate constant decreased by 80 times. The suppression of EEA by NEGB is attributed to the reduction of the defect-assisted EEA process, which we also explain with our theoretical model. Our results provide a synergetic solution to cope with EEA to realize high-intensity 2D light emitters using TMDs.
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Affiliation(s)
- Trang Thu Tran
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Yongjun Lee
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Shrawan Roy
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Thi Uyen Tran
- Department of Smart Fab. Technology, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Youngbum Kim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Takashi Taniguchi
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Kenji Watanabe
- Research Center for Electronic and Optical Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Milorad V Milošević
- Department of Physics, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium
- Instituto de Física, Universidade Federal de Mato Grosso, Cuiabá, Mato Grosso 78060-900, Brazil
| | - Seong Chu Lim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Department of Smart Fab. Technology, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Andrey Chaves
- Department of Physics, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium
- Departamento de Física, Universidade Federal do Ceará, Campus do Pici, C.P. 6030, 60455-900 Fortaleza, Ceará, Brazil
| | - Joon I Jang
- Department of Physics, Sogang University, Seoul 04107, Republic of Korea
| | - Jeongyong Kim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
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3
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Jadczak J, Debus J, Olejnik J, Ho CH, Watanabe K, Taniguchi T, Bryja L. Biexciton and Singlet Trion Upconvert Exciton Photoluminescence in a MoSe 2 Monolayer Supported by Acoustic and Optical K-Valley Phonons. J Phys Chem Lett 2023; 14:8702-8708. [PMID: 37733953 PMCID: PMC10561254 DOI: 10.1021/acs.jpclett.3c01982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 09/18/2023] [Indexed: 09/23/2023]
Abstract
Transition metal dichalcogenide monolayers represent unique platforms for studying both electronic and phononic interactions as well as intra- and intervalley exciton complexes. Here, we investigate the upconversion of exciton photoluminescence in MoSe2 monolayers. Within the nominal transparency window of MoSe2 the exciton emission is enhanced for resonantly addressing the spin-singlet negative trion and neutral biexciton at a few tens of meV below the neutral exciton transition. We identify that the A'1 optical phonon at the K valley provides the energy gain in the upconversion process at the trion resonance, while ZA(K) phonons with their spin- and valley-switching properties support the biexciton driven upconversion of the exciton emission. Interestingly, the latter upconversion process yields unpolarized exciton photoluminescence, while the former also leads to circularly polarized emission. Our study highlights high-order exciton complexes interacting with optical and acoustic K-valley phonons and upconverting light into the bright exciton.
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Affiliation(s)
- Joanna Jadczak
- Department
of Experimental Physics, Wrocław University
of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Joerg Debus
- Department
of Physics, TU Dortmund University, 44227 Dortmund, Germany
| | - Justyna Olejnik
- Department
of Experimental Physics, Wrocław University
of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Ching-Hwa Ho
- Graduate
Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 106, Taiwan
| | - Kenji Watanabe
- National
Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan
| | - Takashi Taniguchi
- National
Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan
| | - Leszek Bryja
- Department
of Experimental Physics, Wrocław University
of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
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4
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Stellino E, D'Alò B, Capitani F, Verseils M, Brubach JB, Roy P, Nucara A, Petrillo C, Postorino P. Far-Infrared Signatures for a Two-Step Pressure-Driven Metallization in Transition Metal Dichalcogenides. J Phys Chem Lett 2023; 14:2133-2140. [PMID: 36802587 DOI: 10.1021/acs.jpclett.3c00199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
We present a high-pressure investigation of the semiconductor-to-metal transition in MoS2 and WS2 carried out by synchrotron-based far-infrared spectroscopy, to reconcile the controversial estimates of the metallization pressure found in the literature and gain new insight into the mechanisms ruling this electronic transition. Two spectral descriptors are found indicative of the onset of metallicity and of the origin of the free carriers in the metallic state: the absorbance spectral weight, whose abrupt increase defines the metallization pressure threshold, and the asymmetric line shape of the E1u peak, whose pressure evolution, interpreted within the Fano model, suggests the electrons in the metallic state originate from n-type doping levels. Combining our results with those reported in the literature, we hypothesize a two-step mechanism is at work in the metallization process, in which the pressure-induced hybridization between doping and conduction band states drives an early metallic behavior, while the band gap closes at higher pressures.
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Affiliation(s)
- Elena Stellino
- University of Perugia, Department of Physics and Geology, via Alessandro Pascoli, 06123, Perugia, Italy
| | - Beatrice D'Alò
- Sapienza University of Rome, Department of Physics, P.le A. Moro 5, 00185, Rome, Italy
| | - Francesco Capitani
- Synchrotron SOLEIL, L'Orme des Merisiers - Départementale 128, 91190 Saint-Aubin, France
| | - Marine Verseils
- Synchrotron SOLEIL, L'Orme des Merisiers - Départementale 128, 91190 Saint-Aubin, France
| | - Jean-Blaise Brubach
- Synchrotron SOLEIL, L'Orme des Merisiers - Départementale 128, 91190 Saint-Aubin, France
| | - Pascale Roy
- Synchrotron SOLEIL, L'Orme des Merisiers - Départementale 128, 91190 Saint-Aubin, France
| | - Alessandro Nucara
- Sapienza University of Rome, Department of Physics, P.le A. Moro 5, 00185, Rome, Italy
| | - Caterina Petrillo
- University of Perugia, Department of Physics and Geology, via Alessandro Pascoli, 06123, Perugia, Italy
| | - Paolo Postorino
- Sapienza University of Rome, Department of Physics, P.le A. Moro 5, 00185, Rome, Italy
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5
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Zhumagulov YV, Vagov A, Gulevich DR, Perebeinos V. Electrostatic and Environmental Control of the Trion Fine Structure in Transition Metal Dichalcogenide Monolayers. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:3728. [PMID: 36364505 PMCID: PMC9656490 DOI: 10.3390/nano12213728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 10/18/2022] [Accepted: 10/19/2022] [Indexed: 06/16/2023]
Abstract
Charged excitons or trions are essential for optical spectra in low-dimensional doped monolayers (ML) of transitional metal dichalcogenides (TMDC). Using a direct diagonalization of the three-body Hamiltonian, we calculate the low-lying trion states in four types of TMDC MLs as a function of doping and dielectric environment. We show that the fine structure of the trion is the result of the interplay between the spin-valley fine structure of the single-particle bands and the exchange interaction. We demonstrate that by variations of the doping and dielectric environment, the fine structure of the trion energy can be tuned, leading to anticrossing of the bright and dark states, with substantial implications for the optical spectra of the TMDC ML.
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Affiliation(s)
| | - Alexei Vagov
- Faculty of Physics, National Research University Higher School of Economics, 101000 Moscow, Russia
| | | | - Vasili Perebeinos
- Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA
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6
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Stellino E, Capitani F, Ripanti F, Verseils M, Petrillo C, Dore P, Postorino P. Broadband infrared study of pressure-tunable Fano resonance and metallization transition in 2H-[Formula: see text]. Sci Rep 2022; 12:17333. [PMID: 36243735 PMCID: PMC9569381 DOI: 10.1038/s41598-022-22089-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 10/10/2022] [Indexed: 11/26/2022] Open
Abstract
High pressure is a proven effective tool for modulating inter-layer interactions in semiconducting transition metal dichalcogenides, which leads to significant band structure changes. Here, we present an extended infrared study of the pressure-induced semiconductor-to-metal transition in 2H-[Formula: see text], which reveals that the metallization process at 13-15 GPa is not associated with the indirect band-gap closure, occurring at 24 GPa. A coherent picture is drawn where n-type doping levels just below the conduction band minimum play a crucial role in the early metallization transition. Doping levels are also responsible for the asymmetric Fano line-shape of the [Formula: see text] infrared-active mode, which has been here detected and analyzed for the first time in a transition metal dichalcogenide compound. The pressure evolution of the phonon profile under pressure shows a symmetrization in the 13-15 GPa pressure range, which occurs simultaneously with the metallization and confirms the scenario proposed for the high pressure behaviour of 2H-[Formula: see text].
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Affiliation(s)
- E. Stellino
- Department of Physics and Geology, University of Perugia, via Alessandro Pascoli, 06123 Perugia, Italy
| | - F. Capitani
- Synchrotron SOLEIL, L’Orme des Merisiers, 91190 Saint-Aubin, Gif-sur-Yvette France
| | - F. Ripanti
- Department of Physics and Geology, University of Perugia, via Alessandro Pascoli, 06123 Perugia, Italy
| | - M. Verseils
- Synchrotron SOLEIL, L’Orme des Merisiers, 91190 Saint-Aubin, Gif-sur-Yvette France
| | - C. Petrillo
- Department of Physics and Geology, University of Perugia, via Alessandro Pascoli, 06123 Perugia, Italy
| | - P. Dore
- Sapienza University, Piazzale Aldo Moro, 2, 00185 Rome, Italy
| | - P. Postorino
- Sapienza University, Piazzale Aldo Moro, 2, 00185 Rome, Italy
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7
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Żuberek E, Majak M, Lubczyński J, Debus J, Watanabe K, Taniguchi T, Ho CH, Bryja L, Jadczak J. Upconversion photoluminescence excitation reveals exciton-trion and exciton-biexciton coupling in hBN/WS[Formula: see text]/hBN van der Waals heterostructures. Sci Rep 2022; 12:13699. [PMID: 35953508 PMCID: PMC9372078 DOI: 10.1038/s41598-022-18104-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 08/05/2022] [Indexed: 11/10/2022] Open
Abstract
Monolayers of transition-metal dichalcogenides with direct band gap located at the binary [Formula: see text] points of the Brillouin zone are promising materials for applications in opto- and spin-electronics due to strongly enhanced Coulomb interactions and specific spin-valley properties. They furthermore represent a unique platform to study electron-electron and electron-phonon interactions in diverse exciton complexes. Here, we demonstrate processes in which the neutral biexciton and two negative trions, namely the spin-triplet and spin-singlet trions, upconvert light into a bright intravalley exciton in an hBN-encapsulated WS[Formula: see text] monolayer. We propose that the energy gains required in the polarized upconversion photoluminescence originate from different interactions including resonant optical phonons, a cooling of resident electrons and a non-local and an anisotropic electron-hole exchange, respectively. The temperature dependence (7-120 K) of the excitonic upconversion intensity obtained at excitation energies corresponding to the biexciton and trions provides insight into an increasing phonon population as well as a thermally enhanced electron scattering. Our study sheds new light on the understanding of excitonic spin and valley properties of van der Waals heterostructures and improves the understanding of photonic upconversion mechanisms in two-dimensional quantum materials.
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Affiliation(s)
- Ewa Żuberek
- Department of Experimental Physics, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Martyna Majak
- Department of Experimental Physics, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Jakub Lubczyński
- Department of Experimental Physics, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Joerg Debus
- Department of Physics, TU Dortmund University, 44227 Dortmund, Germany
| | - Kenji Watanabe
- National Institute for Materials Science, Tsukuba, Ibaraki 305-0044 Japan
| | - Takashi Taniguchi
- National Institute for Materials Science, Tsukuba, Ibaraki 305-0044 Japan
| | - Ching-Hwa Ho
- Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei, 106 Taiwan
| | - Leszek Bryja
- Department of Experimental Physics, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Joanna Jadczak
- Department of Experimental Physics, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
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8
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Covre FS, Faria PE, Gordo VO, de Brito CS, Zhumagulov YV, Teodoro MD, Couto ODD, Misoguti L, Pratavieira S, Andrade MB, Christianen PCM, Fabian J, Withers F, Galvão Gobato Y. Revealing the impact of strain in the optical properties of bubbles in monolayer MoSe 2. NANOSCALE 2022; 14:5758-5768. [PMID: 35348558 DOI: 10.1039/d2nr00315e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Strain plays an important role for the optical properties of monolayer transition metal dichalcogenides (TMDCs). Here, we investigate strain effects in a monolayer MoSe2 sample with a large bubble region using μ-Raman, second harmonic generation (SHG), μ-photoluminescence and magneto μ-photoluminescence at low temperature. Remarkably, our results reveal the presence of a non-uniform strain field and the observation of emission peaks at lower energies which are the signatures of exciton and trion quasiparticles red-shifted by strain effects in the bubble region, in agreement with our theoretical predictions. Furthermore, we have observed that the emission in the strained region decreases the trion binding energy and enhances the valley g-factors as compared to non-strained regions. Considering uniform biaxial strain effects within the unit cell of the TMDC monolayer (ML), our first principles calculations predict the observed enhancement of the exciton valley Zeeman effect. In addition, our results suggest that the exciton-trion fine structure plays an important role for the optical properties of strained TMDC ML. In summary, our study provides fundamental insights on the behaviour of excitons and trions in strained monolayer MoSe2 which are particularly relevant to properly characterize and understand the fine structure of excitonic complexes in strained TMDC systems/devices.
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Affiliation(s)
- F S Covre
- Departamento de Física, Universidade Federal de São Carlos, 13565-905, São Carlos, SP, Brazil.
| | - P E Faria
- Institute for Theoretical Physics, University of Regensburg, 93040 Regensburg, Germany
| | - V O Gordo
- Instituto de Física "Gleb Wataghin", Universidade Estadual de Campinas, 13083-859, Campinas, São Paulo, Brazil
| | - C Serati de Brito
- Departamento de Física, Universidade Federal de São Carlos, 13565-905, São Carlos, SP, Brazil.
| | - Y V Zhumagulov
- Institute for Theoretical Physics, University of Regensburg, 93040 Regensburg, Germany
| | - M D Teodoro
- Departamento de Física, Universidade Federal de São Carlos, 13565-905, São Carlos, SP, Brazil.
| | - O D D Couto
- Instituto de Física "Gleb Wataghin", Universidade Estadual de Campinas, 13083-859, Campinas, São Paulo, Brazil
| | - L Misoguti
- Instituto de Física de São Carlos - Universidade de São Paulo, CEP 13566-590, São Carlos, São Paulo, Brazil
| | - S Pratavieira
- Instituto de Física de São Carlos - Universidade de São Paulo, CEP 13566-590, São Carlos, São Paulo, Brazil
| | - M B Andrade
- Instituto de Física de São Carlos - Universidade de São Paulo, CEP 13566-590, São Carlos, São Paulo, Brazil
| | - P C M Christianen
- High Field Magnet Laboratory (HFML - EMFL), Radboud University, 6525 ED Nijmegen, The Netherlands
| | - J Fabian
- Institute for Theoretical Physics, University of Regensburg, 93040 Regensburg, Germany
| | - F Withers
- College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter EX4 4QF, UK
| | - Y Galvão Gobato
- Departamento de Física, Universidade Federal de São Carlos, 13565-905, São Carlos, SP, Brazil.
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