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Leermakers I, Rubi K, Yang M, Kerdi B, Goiran M, Escoffier W, Rana AS, Smink AEM, Brinkman A, Hilgenkamp H, Maan JC, Zeitler U. Quantum oscillations in an optically-illuminated two-dimensional electron system at the LaAlO 3/SrTiO 3interface. J Phys Condens Matter 2021; 33:465002. [PMID: 34433152 DOI: 10.1088/1361-648x/ac211a] [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: 05/26/2021] [Accepted: 08/25/2021] [Indexed: 06/13/2023]
Abstract
We have investigated the illumination effect on the magnetotransport properties of a two-dimensional electron system at the LaAlO3/SrTiO3interface. The illumination significantly reduces the zero-field sheet resistance, eliminates the Kondo effect at low-temperature, and switches the negative magnetoresistance into the positive one. A large increase in the density of high-mobility carriers after illumination leads to quantum oscillations in the magnetoresistance originating from the Landau quantization. The carrier density (∼2 × 1012 cm-2) and effective mass (∼1.7me) estimated from the oscillations suggest that the high-mobility electrons occupy thedxz/yzsubbands of Ti:t2gorbital extending deep within the conducting sheet of SrTiO3. Our results demonstrate that the illumination which induces additional carriers at the interface can pave the way to control the Kondo-like scattering and study the quantum transport in the complex oxide heterostructures.
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Affiliation(s)
- I Leermakers
- High Field Magnet Laboratory (HFML-EMFL) and Institute for Molecules and Materials, Radboud University, Nijmegen, The Netherlands
| | - K Rubi
- High Field Magnet Laboratory (HFML-EMFL) and Institute for Molecules and Materials, Radboud University, Nijmegen, The Netherlands
| | - M Yang
- Laboratoire National des Champs Magnétiques Intenses (LNCMI-EMFL), Université de Toulouse, CNRS, INSA, UPS, 143 Avenue de Rangueil, 31400 Toulouse, France
| | - B Kerdi
- Laboratoire National des Champs Magnétiques Intenses (LNCMI-EMFL), Université de Toulouse, CNRS, INSA, UPS, 143 Avenue de Rangueil, 31400 Toulouse, France
| | - M Goiran
- Laboratoire National des Champs Magnétiques Intenses (LNCMI-EMFL), Université de Toulouse, CNRS, INSA, UPS, 143 Avenue de Rangueil, 31400 Toulouse, France
| | - W Escoffier
- Laboratoire National des Champs Magnétiques Intenses (LNCMI-EMFL), Université de Toulouse, CNRS, INSA, UPS, 143 Avenue de Rangueil, 31400 Toulouse, France
| | - A S Rana
- MESA + Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - A E M Smink
- MESA + Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - A Brinkman
- MESA + Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - H Hilgenkamp
- MESA + Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - J C Maan
- High Field Magnet Laboratory (HFML-EMFL) and Institute for Molecules and Materials, Radboud University, Nijmegen, The Netherlands
| | - U Zeitler
- High Field Magnet Laboratory (HFML-EMFL) and Institute for Molecules and Materials, Radboud University, Nijmegen, The Netherlands
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2
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Gogoi P, Kamenskyi D, Arslanov DD, Jongma RT, van der Zande WJ, Redlich B, van der Meer AFG, Engelkamp H, Christianen PCM, Maan JC. Magnetoquantum Oscillations at THz Frequencies in InSb. Phys Rev Lett 2017; 119:146603. [PMID: 29053326 DOI: 10.1103/physrevlett.119.146603] [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: 12/23/2016] [Indexed: 06/07/2023]
Abstract
The ac magnetoconductance of bulk InSb at THz frequencies in high magnetic fields, as measured by the transmission of THz radiation, shows a field-induced transmission, which at high temperatures (≈100 K) is well explained with classical magnetoplasma effects (helicon waves). However, at low temperatures (4 K), the transmitted radiation intensity shows magnetoquantum oscillations that represent the Shubnikov-de Haas effect at THz frequencies. At frequencies above 0.9 THz, when the radiation period is shorter than the Drude scattering time, an anomalously high transmission is observed in the magnetic quantum limit that can be interpreted as carrier localization at high frequencies.
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Affiliation(s)
- P Gogoi
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - D Kamenskyi
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
- FELIX Laboratory, Institute for Molecules and Materials, Radboud University, Toernooiveld 7c, 6525 ED Nijmegen, The Netherlands
| | - D D Arslanov
- FELIX Laboratory, Institute for Molecules and Materials, Radboud University, Toernooiveld 7c, 6525 ED Nijmegen, The Netherlands
| | - R T Jongma
- FELIX Laboratory, Institute for Molecules and Materials, Radboud University, Toernooiveld 7c, 6525 ED Nijmegen, The Netherlands
| | - W J van der Zande
- FELIX Laboratory, Institute for Molecules and Materials, Radboud University, Toernooiveld 7c, 6525 ED Nijmegen, The Netherlands
| | - B Redlich
- FELIX Laboratory, Institute for Molecules and Materials, Radboud University, Toernooiveld 7c, 6525 ED Nijmegen, The Netherlands
| | - A F G van der Meer
- FELIX Laboratory, Institute for Molecules and Materials, Radboud University, Toernooiveld 7c, 6525 ED Nijmegen, The Netherlands
| | - H Engelkamp
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - P C M Christianen
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - J C Maan
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
- FELIX Laboratory, Institute for Molecules and Materials, Radboud University, Toernooiveld 7c, 6525 ED Nijmegen, The Netherlands
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3
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Tao W, Singh S, Rossi L, Gerritsen JW, Hendriksen BLM, Khajetoorians AA, Christianen PCM, Maan JC, Zeitler U, Bryant B. A low-temperature scanning tunneling microscope capable of microscopy and spectroscopy in a Bitter magnet at up to 34 T. Rev Sci Instrum 2017; 88:093706. [PMID: 28964167 DOI: 10.1063/1.4995372] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We present the design and performance of a cryogenic scanning tunneling microscope (STM) which operates inside a water-cooled Bitter magnet, which can attain a magnetic field of up to 38 T. Due to the high vibration environment generated by the magnet cooling water, a uniquely designed STM and a vibration damping system are required. The STM scan head is designed to be as compact and rigid as possible, to minimize the effect of vibrational noise as well as fit the size constraints of the Bitter magnet. The STM uses a differential screw mechanism for coarse tip-sample approach, and operates in helium exchange gas at cryogenic temperatures. The reliability and performance of the STM are demonstrated through topographic imaging and scanning tunneling spectroscopy on highly oriented pyrolytic graphite at T = 4.2 K and in magnetic fields up to 34 T.
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Affiliation(s)
- W Tao
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, 6525 ED Nijmegen, The Netherlands
| | - S Singh
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, 6525 ED Nijmegen, The Netherlands
| | - L Rossi
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, 6525 ED Nijmegen, The Netherlands
| | - J W Gerritsen
- Institute for Molecules and Materials, Radboud University, Nijmegen, The Netherlands
| | - B L M Hendriksen
- Institute for Molecules and Materials, Radboud University, Nijmegen, The Netherlands
| | - A A Khajetoorians
- Institute for Molecules and Materials, Radboud University, Nijmegen, The Netherlands
| | - P C M Christianen
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, 6525 ED Nijmegen, The Netherlands
| | - J C Maan
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, 6525 ED Nijmegen, The Netherlands
| | - U Zeitler
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, 6525 ED Nijmegen, The Netherlands
| | - B Bryant
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, 6525 ED Nijmegen, The Netherlands
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4
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Becker J, Tsukamoto A, Kirilyuk A, Maan JC, Rasing T, Christianen PCM, Kimel AV. Ultrafast Magnetism of a Ferrimagnet across the Spin-Flop Transition in High Magnetic Fields. Phys Rev Lett 2017; 118:117203. [PMID: 28368648 DOI: 10.1103/physrevlett.118.117203] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Indexed: 06/07/2023]
Abstract
We show that applying magnetic fields up to 30 T has a dramatic effect on the ultrafast spin dynamics in ferrimagnetic GdFeCo. Upon increasing the field beyond a critical value, the dynamics induced by a femtosecond laser excitation strongly increases in amplitude and slows down significantly. Such a change in spin response is explained by different dynamics of the Gd and FeCo magnetic sublattices following a spin-flop phase transition from a collinear to a noncollinear spin state.
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Affiliation(s)
- J Becker
- Radboud University, Institute for Molecules and Materials, Nijmegen 6525 AJ, The Netherlands
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - A Tsukamoto
- College of Science and Technology, Nihon University, 24-1 Narashinodai 7-chome, Funabashi-shi, Chiba 274-8501, Japan
| | - A Kirilyuk
- Radboud University, Institute for Molecules and Materials, Nijmegen 6525 AJ, The Netherlands
| | - J C Maan
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, Toernooiveld 7, 6525 ED NIJMEGEN, The Netherlands
| | - Th Rasing
- Radboud University, Institute for Molecules and Materials, Nijmegen 6525 AJ, The Netherlands
| | - P C M Christianen
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, Toernooiveld 7, 6525 ED NIJMEGEN, The Netherlands
| | - A V Kimel
- Radboud University, Institute for Molecules and Materials, Nijmegen 6525 AJ, The Netherlands
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Khouri T, Zeitler U, Reichl C, Wegscheider W, Hussey NE, Wiedmann S, Maan JC. Linear Magnetoresistance in a Quasifree Two-Dimensional Electron Gas in an Ultrahigh Mobility GaAs Quantum Well. Phys Rev Lett 2016; 117:256601. [PMID: 28036219 DOI: 10.1103/physrevlett.117.256601] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Indexed: 06/06/2023]
Abstract
We report a high-field magnetotransport study of an ultrahigh mobility (μ[over ¯]≈25×10^{6} cm^{2} V^{-1} s^{-1}) n-type GaAs quantum well. We observe a strikingly large linear magnetoresistance (LMR) up to 33 T with a magnitude of order 10^{5}% onto which quantum oscillations become superimposed in the quantum Hall regime at low temperature. LMR is very often invoked as evidence for exotic quasiparticles in new materials such as the topological semimetals, though its origin remains controversial. The observation of such a LMR in the "simplest system"-with a free electronlike band structure and a nearly defect-free environment-excludes most of the possible exotic explanations for the appearance of a LMR and rather points to density fluctuations as the primary origin of the phenomenon. Both, the featureless LMR at high T and the quantum oscillations at low T follow the empirical resistance rule which states that the longitudinal conductance is directly related to the derivative of the transversal (Hall) conductance multiplied by the magnetic field and a constant factor α that remains unchanged over the entire temperature range. Only at low temperatures, small deviations from this resistance rule are observed beyond ν=1 that likely originate from a different transport mechanism for the composite fermions.
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Affiliation(s)
- T Khouri
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
- Radboud University, Institute of Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - U Zeitler
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
- Radboud University, Institute of Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - C Reichl
- Laboratory for Solid State Physics, ETH Zürich, 8093 Zürich, Switzerland
| | - W Wegscheider
- Laboratory for Solid State Physics, ETH Zürich, 8093 Zürich, Switzerland
| | - N E Hussey
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
- Radboud University, Institute of Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - S Wiedmann
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
- Radboud University, Institute of Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - J C Maan
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
- Radboud University, Institute of Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
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6
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Rikken RSM, Engelkamp H, Nolte RJM, Maan JC, van Hest JCM, Wilson DA, Christianen PCM. Shaping polymersomes into predictable morphologies via out-of-equilibrium self-assembly. Nat Commun 2016; 7:12606. [PMID: 27558520 PMCID: PMC5007325 DOI: 10.1038/ncomms12606] [Citation(s) in RCA: 110] [Impact Index Per Article: 13.8] [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: 11/17/2015] [Accepted: 07/18/2016] [Indexed: 02/08/2023] Open
Abstract
Polymersomes are bilayer vesicles, self-assembled from amphiphilic block copolymers. They are versatile nanocapsules with adjustable properties, such as flexibility, permeability, size and functionality. However, so far no methodological approach to control their shape exists. Here we demonstrate a mechanistically fully understood procedure to precisely control polymersome shape via an out-of-equilibrium process. Carefully selecting osmotic pressure and permeability initiates controlled deflation, resulting in transient capsule shapes, followed by reinflation of the polymersomes. The shape transformation towards stomatocytes, bowl-shaped vesicles, was probed with magnetic birefringence, permitting us to stop the process at any intermediate shape in the phase diagram. Quantitative electron microscopy analysis of the different morphologies reveals that this shape transformation proceeds via a long-predicted hysteretic deflation-inflation trajectory, which can be understood in terms of bending energy. Because of the high degree of controllability and predictability, this study provides the design rules for accessing polymersomes with all possible different shapes.
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Affiliation(s)
- R S M Rikken
- Institute for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.,High Field Magnet Laboratory (HFML-EMFL), Radboud University Nijmegen, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - H Engelkamp
- Institute for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.,High Field Magnet Laboratory (HFML-EMFL), Radboud University Nijmegen, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - R J M Nolte
- Institute for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - J C Maan
- Institute for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.,High Field Magnet Laboratory (HFML-EMFL), Radboud University Nijmegen, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - J C M van Hest
- Institute for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - D A Wilson
- Institute for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - P C M Christianen
- Institute for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.,High Field Magnet Laboratory (HFML-EMFL), Radboud University Nijmegen, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
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7
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De Luca M, Polimeni A, Fonseka HA, Meaney AJ, Christianen PCM, Maan JC, Paiman S, Tan HH, Mura F, Jagadish C, Capizzi M. Magneto-optical properties of wurtzite-phase InP nanowires. Nano Lett 2014; 14:4250-4256. [PMID: 24972081 DOI: 10.1021/nl500870e] [Citation(s) in RCA: 7] [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] [Indexed: 06/03/2023]
Abstract
The possibility to grow in zincblende (ZB) and/or wurtzite (WZ) crystal phase widens the potential applications of semiconductor nanowires (NWs). This is particularly true in technologically relevant III-V compounds, such as GaAs, InAs, and InP, for which WZ is not available in bulk form. The WZ band structure of many III-V NWs has been widely studied. Yet, transport (that is, carrier effective mass) and spin (that is, carrier g-factor) properties are almost experimentally unknown. We address these issues in a well-characterized material: WZ indium phosphide. The value and anisotropy of the reduced mass (μ exc) and g-factor (g exc) of the band gap exciton are determined by photoluminescence measurements under intense magnetic fields (B, up to 28 T) applied along different crystallographic directions. μ exc is 14% greater in WZ NWs than in a ZB bulk reference and it is 6% greater in a plane containing the WZ ĉ axis than in a plane orthogonal to ĉ. The Zeeman splitting is markedly anisotropic with g exc = |ge| = 1.4 for B⊥ĉ (where ge is the electron g-factor) and g exc = |ge - gh,//| = 3.5 for B//ĉ (where gh,// is the hole g-factor). A noticeable B-induced circular dichroism of the emitted photons is found only for B//ĉ, as expected in WZ-phase materials.
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Affiliation(s)
- M De Luca
- Dipartimento di Fisica and CNISM, Sapienza Università di Roma , Piazzale A. Moro 2, 00185 Roma, Italy
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8
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van Rhee PG, Zijlstra P, Verhagen TGA, Aarts J, Katsnelson MI, Maan JC, Orrit M, Christianen PCM. Giant magnetic susceptibility of gold nanorods detected by magnetic alignment. Phys Rev Lett 2013; 111:127202. [PMID: 24093295 DOI: 10.1103/physrevlett.111.127202] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Indexed: 06/02/2023]
Abstract
We have determined the magnetic properties of single-crystalline Au nanorods in solution using an optically detected magnetic alignment technique. The rods exhibit a large anisotropy in the magnetic volume susceptibility (Δχ(V)). Δχ(V) increases with decreasing rod size and increasing aspect ratio and corresponds to an average volume susceptibility (χ(V)), which is drastically enhanced relative to bulk Au. This high value of χ(V) is confirmed by SQUID magnetometry and is temperature independent (between 5 and 300 K). Given this peculiar size, shape, and temperature dependence, we speculate that the enhanced χ(V) is the result of orbital magnetism due to mesoscopic electron trajectories within the nanorods.
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Affiliation(s)
- P G van Rhee
- High Field Magnet Laboratory, Institute of Molecules and Materials, Radboud University Nijmegen, Toernooiveld 7, 6525 ED Nijmegen, Netherlands
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9
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Manyuhina OV, Tordini G, Bras W, Maan JC, Christianen PCM. Doubly periodic instability pattern in a smectic-A liquid crystal. Phys Rev E Stat Nonlin Soft Matter Phys 2013; 87:050501. [PMID: 23767471 DOI: 10.1103/physreve.87.050501] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Indexed: 06/02/2023]
Abstract
We report the observation of a doubly periodic surface defect pattern in the liquid crystal 8CB, formed during the nematic-smectic-A phase transition. The pattern results from the antagonistic alignment of the 8CB molecules, which is homeotropic at the surface and planar in the bulk of the sample cell. Within the continuum Landau-de Gennes theory of smectic liquid crystals, we find that the long period (≈10 μm) of the pattern is given by the balance between the surface anchoring and the elastic energy of curvature wall defects. The short period (≈1 μm) we attribute to a saddle-splay distortion, leading to a nonzero Gaussian curvature and causing the curvature walls to break up.
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Affiliation(s)
- O V Manyuhina
- Nordita, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, SE-106 91 Stockholm, Sweden.
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McCollam A, van Rhee PG, Rook J, Kampert E, Zeitler U, Maan JC. High sensitivity magnetometer for measuring the isotropic and anisotropic magnetisation of small samples. Rev Sci Instrum 2011; 82:053909. [PMID: 21639520 DOI: 10.1063/1.3595676] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We describe how the full, isotropic and anisotropic, magnetisation of samples as small as tens of micrometers in size can be sensitively measured using a piezoresistive microcantilever and a small, moveable ferromagnet. Depending on the position of the ferromagnet, a strong but highly local field gradient of up to ∼4200 T/m can be applied at the sample or removed completely during a single measurement. In this way, the magnetic force and torque on the sample can be independently determined without moving the sample or cycling the experimental system. The technique can be used from millikelvin temperatures to ∼85 K and in magnetic fields from 2 T to the highest fields available. We demonstrate its application in measurements of the semimagnetic semiconductor Hg(1 - x)Fe(x)Se, where we achieved a moment sensitivity of better than 2.5 × 10(-14) J/T for both isotropic and anisotropic components.
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Affiliation(s)
- A McCollam
- High Field Magnet Laboratory, Institute of Molecules and Materials, Radboud University Nijmegen, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands.
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11
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Gielen JC, Ver Heyen A, Klyatskaya S, Vanderlinden W, Höger S, Maan JC, De Feyter S, Christianen PCM. Aggregation Kinetics of Macrocycles Detected by Magnetic Birefringence. J Am Chem Soc 2009; 131:14134-5. [DOI: 10.1021/ja904816m] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jeroen C. Gielen
- IMM, High Field Magnet Laboratory, Radboud University Nijmegen, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands, Division of Molecular and Nanomaterials and Institute of Nanoscale Physics and Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200-F, 3001 Leuven, Belgium, Institute für Technische Chemie und Polymerchemie, Universität Karlsruhe, Engeserstrasse 16, 76128 Karlsruhe, Germany, and Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms-Universität Bonn,
| | - An Ver Heyen
- IMM, High Field Magnet Laboratory, Radboud University Nijmegen, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands, Division of Molecular and Nanomaterials and Institute of Nanoscale Physics and Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200-F, 3001 Leuven, Belgium, Institute für Technische Chemie und Polymerchemie, Universität Karlsruhe, Engeserstrasse 16, 76128 Karlsruhe, Germany, and Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms-Universität Bonn,
| | - Svetlana Klyatskaya
- IMM, High Field Magnet Laboratory, Radboud University Nijmegen, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands, Division of Molecular and Nanomaterials and Institute of Nanoscale Physics and Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200-F, 3001 Leuven, Belgium, Institute für Technische Chemie und Polymerchemie, Universität Karlsruhe, Engeserstrasse 16, 76128 Karlsruhe, Germany, and Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms-Universität Bonn,
| | - Willem Vanderlinden
- IMM, High Field Magnet Laboratory, Radboud University Nijmegen, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands, Division of Molecular and Nanomaterials and Institute of Nanoscale Physics and Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200-F, 3001 Leuven, Belgium, Institute für Technische Chemie und Polymerchemie, Universität Karlsruhe, Engeserstrasse 16, 76128 Karlsruhe, Germany, and Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms-Universität Bonn,
| | - Sigurd Höger
- IMM, High Field Magnet Laboratory, Radboud University Nijmegen, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands, Division of Molecular and Nanomaterials and Institute of Nanoscale Physics and Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200-F, 3001 Leuven, Belgium, Institute für Technische Chemie und Polymerchemie, Universität Karlsruhe, Engeserstrasse 16, 76128 Karlsruhe, Germany, and Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms-Universität Bonn,
| | - J. C. Maan
- IMM, High Field Magnet Laboratory, Radboud University Nijmegen, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands, Division of Molecular and Nanomaterials and Institute of Nanoscale Physics and Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200-F, 3001 Leuven, Belgium, Institute für Technische Chemie und Polymerchemie, Universität Karlsruhe, Engeserstrasse 16, 76128 Karlsruhe, Germany, and Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms-Universität Bonn,
| | - Steven De Feyter
- IMM, High Field Magnet Laboratory, Radboud University Nijmegen, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands, Division of Molecular and Nanomaterials and Institute of Nanoscale Physics and Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200-F, 3001 Leuven, Belgium, Institute für Technische Chemie und Polymerchemie, Universität Karlsruhe, Engeserstrasse 16, 76128 Karlsruhe, Germany, and Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms-Universität Bonn,
| | - Peter C. M. Christianen
- IMM, High Field Magnet Laboratory, Radboud University Nijmegen, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands, Division of Molecular and Nanomaterials and Institute of Nanoscale Physics and Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200-F, 3001 Leuven, Belgium, Institute für Technische Chemie und Polymerchemie, Universität Karlsruhe, Engeserstrasse 16, 76128 Karlsruhe, Germany, and Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms-Universität Bonn,
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12
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Gielen JC, Wolffs M, Portale G, Bras W, Henze O, Kilbinger AFM, Feast WJ, Maan JC, Schenning APHJ, Christianen PCM. Molecular organization of cylindrical sexithiophene aggregates measured by X-ray scattering and magnetic alignment. Langmuir 2009; 25:1272-1276. [PMID: 19170640 DOI: 10.1021/la8039913] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We have determined the internal organization of elongated sexithiophene aggregates in solution by combining small-angle X-ray scattering and magnetic birefringence experiments. The different aggregate axes can be probed independently by performing the experiments on magnetically aligned aggregates. We have found multiwalled cylindrical aggregates consisting of radially oriented sexithiophene molecules with pi-pi-stacking in the tangential direction, a structure that is considerably different from those previously found in other solvents. The aggregate morphology of this semiconducting material can thus be tuned by using different solvents, which offers the attractive perspective to steer chemical self-assembly toward nanostructures with desired functionalities, especially in combination with the alignment in a magnetic field.
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Affiliation(s)
- Jeroen C Gielen
- IMM, High Field Magnet Laboratory HFML, Radboud University Nijmegen, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
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13
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Gielen JC, Shklyarevskiy IO, Schenning APHJ, Christianen PCM, Maan JC. Using magnetic birefringence to determine the molecular arrangement of supramolecular nanostructures. Sci Technol Adv Mater 2009; 10:014601. [PMID: 27877252 PMCID: PMC5109616 DOI: 10.1088/1468-6996/10/1/014601] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2008] [Revised: 05/22/2009] [Accepted: 10/27/2008] [Indexed: 06/01/2023]
Abstract
Supramolecular aggregates can be aligned in solution using a magnetic field. Because of the optical anisotropy of the molecular building blocks, the alignment results in an anisotropic refractive index of the solution parallel and perpendicular to the magnetic field. We present a model for calculating the magnetic birefringence, using solely the magnetic susceptibilities and optical polarizabilities of the molecules, for any molecular arrangement. We demonstrate that magnetic birefringence is a very sensitive tool for determining the molecular organization within supramolecular aggregates.
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Affiliation(s)
- Jeroen C Gielen
- IMM, High Field Magnet Laboratory HFML, University of Nijmegen, Toernooiveld 7, 6525 ED NIJMEGEN, The Netherlands
| | - Igor O Shklyarevskiy
- IMM, High Field Magnet Laboratory HFML, University of Nijmegen, Toernooiveld 7, 6525 ED NIJMEGEN, The Netherlands
| | - Albertus P H J Schenning
- Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands
| | - Peter C M Christianen
- IMM, High Field Magnet Laboratory HFML, University of Nijmegen, Toernooiveld 7, 6525 ED NIJMEGEN, The Netherlands
| | - J C Maan
- IMM, High Field Magnet Laboratory HFML, University of Nijmegen, Toernooiveld 7, 6525 ED NIJMEGEN, The Netherlands
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14
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Giesbers AJM, Zeitler U, Katsnelson MI, Ponomarenko LA, Mohiuddin TM, Maan JC. Quantum-Hall activation gaps in graphene. Phys Rev Lett 2007; 99:206803. [PMID: 18233175 DOI: 10.1103/physrevlett.99.206803] [Citation(s) in RCA: 6] [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: 04/18/2007] [Indexed: 05/25/2023]
Abstract
We have measured the quantum-Hall activation gaps in graphene at filling factors nu=2 and nu=6 for magnetic fields up to 32 T and temperatures from 4 to 300 K. The nu=6 gap can be described by thermal excitation to broadened Landau levels with a width of 400 K. In contrast, the gap measured at nu=2 is strongly temperature and field dependent and approaches the expected value for sharp Landau levels for fields B>20 T and temperatures T>100 K. We explain this surprising behavior by a narrowing of the lowest Landau level.
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Affiliation(s)
- A J M Giesbers
- High Field Magnet Laboratory, Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands.
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15
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Kleemans NAJM, Bominaar-Silkens IMA, Fomin VM, Gladilin VN, Granados D, Taboada AG, García JM, Offermans P, Zeitler U, Christianen PCM, Maan JC, Devreese JT, Koenraad PM. Oscillatory persistent currents in self-assembled quantum rings. Phys Rev Lett 2007; 99:146808. [PMID: 17930703 DOI: 10.1103/physrevlett.99.146808] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2007] [Indexed: 05/25/2023]
Abstract
We report the direct measurement of the persistent current carried by a single electron by means of magnetization experiments on self-assembled InAs/GaAs quantum rings. We measured the first Aharonov-Bohm oscillation at a field of 14 T, in perfect agreement with our model based on the structural properties determined by cross-sectional scanning tunneling microscopy measurements. The observed oscillation magnitude of the magnetic moment per electron is remarkably large for the topology of our nanostructures, which are singly connected and exhibit a pronounced shape asymmetry.
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16
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Brinkman A, Huijben M, van Zalk M, Huijben J, Zeitler U, Maan JC, van der Wiel WG, Rijnders G, Blank DHA, Hilgenkamp H. Magnetic effects at the interface between non-magnetic oxides. Nat Mater 2007; 6:493-6. [PMID: 17546035 DOI: 10.1038/nmat1931] [Citation(s) in RCA: 460] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2006] [Accepted: 05/02/2007] [Indexed: 05/15/2023]
Abstract
The electronic reconstruction at the interface between two insulating oxides can give rise to a highly conductive interface. Here we show how, in analogy to this remarkable interface-induced conductivity, magnetism can be induced at the interface between the otherwise non-magnetic insulating perovskites SrTiO3 and LaAlO3. A large negative magnetoresistance of the interface is found, together with a logarithmic temperature dependence of the sheet resistance. At low temperatures, the sheet resistance reveals magnetic hysteresis. Magnetic ordering is a key issue in solid-state science and its underlying mechanisms are still the subject of intense research. In particular, the interplay between localized magnetic moments and the spin of itinerant conduction electrons in a solid gives rise to intriguing many-body effects such as Ruderman-Kittel-Kasuya-Yosida interactions, the Kondo effect and carrier-induced ferromagnetism in diluted magnetic semiconductors. The conducting oxide interface now provides a versatile system to induce and manipulate magnetic moments in otherwise non-magnetic materials.
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Affiliation(s)
- A Brinkman
- Faculty of Science and Technology and MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands.
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17
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Manyuhina OV, Shklyarevskiy IO, Jonkheijm P, Christianen PCM, Fasolino A, Katsnelson MI, Schenning APHJ, Meijer EW, Henze O, Kilbinger AFM, Feast WJ, Maan JC. Anharmonic magnetic deformation of self-assembled molecular nanocapsules. Phys Rev Lett 2007; 98:146101. [PMID: 17501291 DOI: 10.1103/physrevlett.98.146101] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2006] [Indexed: 05/15/2023]
Abstract
High magnetic fields were used to deform spherical nanocapsules, self-assembled from bolaamphiphilic sexithiophene molecules. At low fields the deformation--measured through linear birefringence-scales quadratically with the capsule radius and with the magnetic field strength. These data confirm a long standing theoretical prediction [W. Helfrich, Phys. Lett. A 43, 409 (1973)10.1016/0375-9601(73)90396-4], and permit the determination of the bending rigidity of the capsules as (2.6+/-0.8) x 10(-21) J. At high fields, an enhanced rigidity is found which cannot be explained within the Helfrich model. We propose a complete form of the free energy functional that accounts for this behavior, and allows discussion of the formation and stability of nanocapsules in solution.
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Affiliation(s)
- O V Manyuhina
- Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
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18
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Novoselov KS, Jiang Z, Zhang Y, Morozov SV, Stormer HL, Zeitler U, Maan JC, Boebinger GS, Kim P, Geim AK. Room-Temperature Quantum Hall Effect in Graphene. Science 2007; 315:1379. [PMID: 17303717 DOI: 10.1126/science.1137201] [Citation(s) in RCA: 917] [Impact Index Per Article: 53.9] [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 quantum Hall effect (QHE), one example of a quantum phenomenon that occurs on a truly macroscopic scale, has attracted intense interest since its discovery in 1980 and has helped elucidate many important aspects of quantum physics. It has also led to the establishment of a new metrological standard, the resistance quantum. Disappointingly, however, the QHE has been observed only at liquid-helium temperatures. We show that in graphene, in a single atomic layer of carbon, the QHE can be measured reliably even at room temperature, which makes possible QHE resistance standards becoming available to a broader community, outside a few national institutions.
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Affiliation(s)
- K S Novoselov
- Department of Physics, University of Manchester, Manchester M13 9PL, UK
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19
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Poodt PWG, Heijna MCR, Christianen PCM, van Enckevort WJP, de Grip WJ, Tsukamoto K, Maan JC, Vlieg E. Microgravity crystal growth in a magnet. Acta Crystallogr A 2006. [DOI: 10.1107/s010876730609979x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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20
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Shklyarevskiy IO, Jonkheijm P, Christianen PCM, Schenning APHJ, Del Guerzo A, Desvergne JP, Meijer EW, Maan JC. Magnetic alignment of self-assembled anthracene organogel fibers. Langmuir 2005; 21:2108-2112. [PMID: 15751994 DOI: 10.1021/la047166o] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
High magnetic fields are shown to be remarkably effective to orient self-assembled 2,3-bis-n-decyloxyanthracene (DDOA) fibers during organogel preparation. Magnetic orientation of DDOA results in a highly organized material displaying a fiber-orientation order parameter of 0.85, a large linear birefringence, and fluorescence dichroism. The aligned organogel is stable after removal of the magnetic field at room temperature and consists of fibers oriented perpendicular to the magnetic field direction, as shown by scanning electron microscopy. Models for the molecular organization within the gel fibers are discussed upon quantitative analysis of the birefringence. Prospectively, magnetic alignment can be used to improve specific properties of organogel materials.
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Affiliation(s)
- Igor O Shklyarevskiy
- High Field Magnet Laboratory HFML, Radboud University Nijmegen, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
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21
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Reuter D, Kailuweit P, Wieck AD, Zeitler U, Wibbelhoff O, Meier C, Lorke A, Maan JC. Coulomb-interaction-induced incomplete shell filling in the hole system of InAs quantum dots. Phys Rev Lett 2005; 94:026808. [PMID: 15698214 DOI: 10.1103/physrevlett.94.026808] [Citation(s) in RCA: 2] [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: 05/03/2004] [Indexed: 05/24/2023]
Abstract
We have studied the hole charging spectra of self-assembled InAs quantum dots in perpendicular magnetic fields by capacitance-voltage spectroscopy. From the magnetic-field dependence of the individual peaks we conclude that the s-like ground state is completely filled with two holes but that the fourfold degenerate p shell is only half filled with two holes before the filling of the d shell starts. The resulting six-hole ground state is highly polarized. This incomplete shell filling can be explained by the large influence of the Coulomb interaction in this system.
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Affiliation(s)
- D Reuter
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, D-44799 Bochum, Germany
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22
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Shklyarevskiy IO, Jonkheijm P, Christianen PCM, Schenning APHJ, Meijer EW, Henze O, Kilbinger AFM, Feast WJ, Del Guerzo A, Desvergne JP, Maan JC. Magnetic Deformation of Self-Assembled Sexithiophene Spherical Nanocapsules. J Am Chem Soc 2005; 127:1112-3. [PMID: 15669845 DOI: 10.1021/ja0431096] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report the experimental observation of magnetic field deformation of spherical nanocapsules, self-assembled from sexithiophene molecules, into oblate spheroids, confirming a long-standing theoretical prediction. The magnetically deformed objects can be trapped in a compatible organogel to make them suitable for further investigations and applications. Our results show that strong magnetic forces can be effectively used, in a contact-free manner, as a tool to control the self-organization of a whole class of functional organic molecules.
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Affiliation(s)
- Igor O Shklyarevskiy
- High Field Magnet Laboratory, Radboud University Nijmegen, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
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23
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Shklyarevskiy IO, Christianen PCM, Aret E, Meekes H, Vlieg E, Deroover G, Callant P, van Meervelt L, Maan JC. Determination of the Molecular Arrangement Inside Cyanine Dye Aggregates by Magnetic Orientation. J Phys Chem B 2004. [DOI: 10.1021/jp049945j] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- I. O. Shklyarevskiy
- High Field Magnet Laboratory, NSRIM, University of Nijmegen, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands, Department of Solid State Chemistry, NSRIM, University of Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands, AGFA-Gevaert N. V., Septestraat 27, B-2640, Mortsel, Belgium, and Department of Chemistry, KULeuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium
| | - P. C. M. Christianen
- High Field Magnet Laboratory, NSRIM, University of Nijmegen, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands, Department of Solid State Chemistry, NSRIM, University of Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands, AGFA-Gevaert N. V., Septestraat 27, B-2640, Mortsel, Belgium, and Department of Chemistry, KULeuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium
| | - E. Aret
- High Field Magnet Laboratory, NSRIM, University of Nijmegen, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands, Department of Solid State Chemistry, NSRIM, University of Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands, AGFA-Gevaert N. V., Septestraat 27, B-2640, Mortsel, Belgium, and Department of Chemistry, KULeuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium
| | - H. Meekes
- High Field Magnet Laboratory, NSRIM, University of Nijmegen, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands, Department of Solid State Chemistry, NSRIM, University of Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands, AGFA-Gevaert N. V., Septestraat 27, B-2640, Mortsel, Belgium, and Department of Chemistry, KULeuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium
| | - E. Vlieg
- High Field Magnet Laboratory, NSRIM, University of Nijmegen, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands, Department of Solid State Chemistry, NSRIM, University of Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands, AGFA-Gevaert N. V., Septestraat 27, B-2640, Mortsel, Belgium, and Department of Chemistry, KULeuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium
| | - G. Deroover
- High Field Magnet Laboratory, NSRIM, University of Nijmegen, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands, Department of Solid State Chemistry, NSRIM, University of Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands, AGFA-Gevaert N. V., Septestraat 27, B-2640, Mortsel, Belgium, and Department of Chemistry, KULeuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium
| | - P. Callant
- High Field Magnet Laboratory, NSRIM, University of Nijmegen, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands, Department of Solid State Chemistry, NSRIM, University of Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands, AGFA-Gevaert N. V., Septestraat 27, B-2640, Mortsel, Belgium, and Department of Chemistry, KULeuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium
| | - L. van Meervelt
- High Field Magnet Laboratory, NSRIM, University of Nijmegen, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands, Department of Solid State Chemistry, NSRIM, University of Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands, AGFA-Gevaert N. V., Septestraat 27, B-2640, Mortsel, Belgium, and Department of Chemistry, KULeuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium
| | - J. C. Maan
- High Field Magnet Laboratory, NSRIM, University of Nijmegen, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands, Department of Solid State Chemistry, NSRIM, University of Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands, AGFA-Gevaert N. V., Septestraat 27, B-2640, Mortsel, Belgium, and Department of Chemistry, KULeuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium
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24
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Possanzini C, Fletcher R, Coleridge PT, Feng Y, Williams RL, Maan JC. Diffusion thermopower of a two-dimensional hole gas in SiGe in a quantum Hall insulating state. Phys Rev Lett 2003; 90:176601. [PMID: 12786087 DOI: 10.1103/physrevlett.90.176601] [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: 12/01/2002] [Indexed: 05/24/2023]
Abstract
Both the temperature dependence of resistivity and thermopower of a two-dimensional hole gas in SiGe show a reentrant metal-insulator transition at filling factor nu=1.5, but with strikingly different behavior of the two coefficients. As the temperature is decreased in the insulating state, the resistivity diverges exponentially while the thermopower decreases rapidly, suggesting that the insulating state is due to the presence of a mobility edge rather than a gap at the Fermi energy.
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Affiliation(s)
- C Possanzini
- Research Institute for Materials, High Field Magnet Laboratory, University of Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
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25
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Boamfa MI, Viertler K, Wewerka A, Stelzer F, Christianen PCM, Maan JC. Magnetic-field-induced changes of the isotropic-nematic phase transition in side-chain polymer liquid crystals. Phys Rev E Stat Nonlin Soft Matter Phys 2003; 67:050701. [PMID: 12786124 DOI: 10.1103/physreve.67.050701] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2002] [Indexed: 05/24/2023]
Abstract
The isotropic-nematic (I-N) phase transition of side-chain polymer liquid crystals is intrinsically a weak first-order transition with a biphasic region spread over a wide temperature interval. In the presence of high magnetic fields we find the I-N transition to become a strong first order. The I-N biphasic region shrinks its temperature window as larger magnetic fields are applied, until it completely disappears and the transition completes at a fixed temperature. We interpret this behavior as a consequence of the nonlinear coupling of the magnetic field to the system free energy, via the suppression of the order fluctuations in the nematic mesophase at the I-N transition crossing.
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Affiliation(s)
- M I Boamfa
- Research Institute for Materials, High Field Magnet Laboratory, University of Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands.
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26
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Boamfa MI, Viertler K, Wewerka A, Stelzer F, Christianen PCM, Maan JC. Mesogene-polymer backbone coupling in side-chain polymer liquid crystals, studied by high magnetic-field-induced alignment. Phys Rev Lett 2003; 90:025501. [PMID: 12570554 DOI: 10.1103/physrevlett.90.025501] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2002] [Indexed: 05/24/2023]
Abstract
We show that cooling side chain polymer liquid crystals in a magnetic field, from the isotropic to nematic and subsequently to the glass phase, results in a macroscopically ordered, transparent, and strongly birefringent material. The aligned samples retain their properties after the field is removed and can be dealigned only by heating them to the isotropic phase. To induce alignment, a threshold field B(th) is necessary, which strongly depends on the chemical structure details. B(th) reflects the strength of mesogene-polymer backbone coupling, and we will show that this interaction is responsible for the stability of the induced alignment at zero field.
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Affiliation(s)
- M I Boamfa
- Research Institute for Materials, High Field Magnet Laboratory, University of Nijmegen, Toernoiveld 1, 6525 ED, The Netherlands.
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27
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Boamfa MI, Kim MW, Maan JC, Rasing T. Observation of surface and bulk phase transitions in nematic liquid crystals. Nature 2003; 421:149-52. [PMID: 12520297 DOI: 10.1038/nature01331] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2002] [Accepted: 11/26/2002] [Indexed: 11/09/2022]
Abstract
The behaviour of liquid crystal (LC) molecules near a surface is of both fundamental and technological interest: it gives rise to various surface phase-transition and wetting phenomena, and surface-induced ordering of the LC molecules is integral to the operation of LC displays. Here we report the observation of a pure isotropic-nematic (IN) surface phase transition-clearly separated from the bulk IN transition-in a nematic LC on a substrate. Differences in phase behaviour between surface and bulk are expected, but have hitherto proved difficult to distinguish, owing in part to the close proximity of their transition temperatures. We have overcome these difficulties by using a mixture of nematic LCs: small, surface-induced composition variations lead to complete separation of the surface and bulk transitions, which we then study independently as a function of substrate and applied magnetic field. We find the surface IN transition to be of first order on surfaces with a weak anchoring energy and continuous on surfaces with a strong anchoring. We show that the presence of high magnetic fields does not change the surface IN transition temperature, whereas the bulk IN transition temperature increases with field. We attribute this to the interaction energy between the surface and bulk phases, which is tuned by magnetic-field-induced order in the surface-wetting layer.
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Affiliation(s)
- M I Boamfa
- NSRIM Institute and High Field Magnet Laboratory, University of Nijmegen, Toernooiveld 1, 6525 ED, Nijmegen, The Netherlands.
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28
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Shklyarevskiy IO, Boamfa MI, Christianen PCM, Touhari F, van Kempen H, Deroover G, Callant P, Maan JC. Magnetic field induced alignment of cyanine dye J-aggregates. J Chem Phys 2002. [DOI: 10.1063/1.1471555] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Sanvitto D, Pulizzi F, Shields AJ, Christianen PC, Holmes SN, Simmons MY, Ritchie DA, Maan JC, Pepper M. Observation of charge transport by negatively charged excitons. Science 2001; 294:837-9. [PMID: 11577201 DOI: 10.1126/science.1064847] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
We report transport of electron-hole complexes in semiconductor quantum wells under applied electric fields. Negatively charged excitons (X-), created by laser excitation of a high electron mobility transistor, are observed to drift upon applying a voltage between the source and drain. In contrast, neutral excitons do not drift under similar conditions. The X- mobility is found to be as high as 6.5 x 10(4) cm2 V-1 s-1. The results demonstrate that X- exists as a free particle in the best-quality samples and suggest that light emission from opto-electronic devices can be manipulated through exciton drift under applied electric fields.
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Affiliation(s)
- D Sanvitto
- Toshiba Research Europe Limited, Cambridge Research Laboratory, 260 Cambridge Science Park, Milton Road, Cambridge, CB4 0WE, UK
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Ebert G, Klitzing KV, Maan JC, Remenyi G, Probst C, Weimann G, Schlapp W. Fractional quantum Hall effect at filling factors up to ν=3. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0022-3719/17/29/004] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Parlangeli A, Christianen P, Geim AK, Maan JC, Eaves L, Heneni M. Magneto-Optical Study of Correlated Electron–Hole Layers in Single-Barrier Heterostructures. ACTA ACUST UNITED AC 1997. [DOI: 10.1002/1521-396x(199711)164:1<587::aid-pssa587>3.0.co;2-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Tieke B, Fletcher R, Maan JC, Dobrowolski W, Mycielski A, Wittlin A. Magnetothermoelectric properties of the degenerate semiconductor HgSe:Fe. Phys Rev B Condens Matter 1996; 54:10565-10574. [PMID: 9984852 DOI: 10.1103/physrevb.54.10565] [Citation(s) in RCA: 5] [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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Tieke B, Zeitler U, Fletcher R, Wiegers SA, Geim AK, Maan JC, Henini M. Even denominator filling factors in the thermoelectric power of a two-dimensional electron gas. Phys Rev Lett 1996; 76:3630-3633. [PMID: 10061016 DOI: 10.1103/physrevlett.76.3630] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Kemerink M, Koenraad PM, Christianen PC, Geim AK, Maan JC, Wolter JH, Henini M. Enhancement of spin-dependent hole delocalization in degenerate asymmetric double quantum wells. Phys Rev B Condens Matter 1996; 53:10000-10007. [PMID: 9982565 DOI: 10.1103/physrevb.53.10000] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Lok JG, Geim AK, Maan JC, Marmorkos I, Peeters FM, Mori N, Eaves L, Foster TJ, Main PC, Sakai JW, Henini M. D- centers probed by resonant tunneling spectroscopy. Phys Rev B Condens Matter 1996; 53:9554-9557. [PMID: 9982498 DOI: 10.1103/physrevb.53.9554] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [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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Volk M, Lutgen S, Marschner T, Stolz W, Göbel EO, Christianen PC, Maan JC. Carrier effective masses in symmetrically strained (GaIn)As/Ga(PAs) multiple-quantum-well structures. Phys Rev B Condens Matter 1995; 52:11096-11104. [PMID: 9980207 DOI: 10.1103/physrevb.52.11096] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [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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Kutter C, Moll HP, Zuckermann H, Maan JC, Wyder P. Electron-spin echoes at 604 GHz using far infrared lasers. Phys Rev Lett 1995; 74:2925-2928. [PMID: 10058059 DOI: 10.1103/physrevlett.74.2925] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Stepniewski R, Potemski M, Buhmann H, Toet D, Maan JC, Martinez G, Knap W, Raymond A, Etienne B. Magneto-optical spectroscopy of free- and bound-electron-hole excitations in the presence of a two-dimensional electron gas. Phys Rev B Condens Matter 1994; 50:11895-11901. [PMID: 9975329 DOI: 10.1103/physrevb.50.11895] [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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Willing B, Maan JC. Nonlinear transport in semi-insulating GaAs: Critical fields and nucleation of high-field domains. Phys Rev B Condens Matter 1994; 49:13995-13998. [PMID: 10010351 DOI: 10.1103/physrevb.49.13995] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [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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Heberle AP, Oestreich M, Haacke S, Rühle WW, Maan JC, Köhler K. Direct observation of resonant tunneling dynamics in high magnetic fields. Phys Rev Lett 1994; 72:1522-1525. [PMID: 10055630 DOI: 10.1103/physrevlett.72.1522] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Liu PY, Maan JC. Optical properties of InSb between 300 and 700 K. II. Magneto-optical experiments. Phys Rev B Condens Matter 1993; 47:16279-16285. [PMID: 10006053 DOI: 10.1103/physrevb.47.16279] [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: 11/07/2022]
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Liu PY, Maan JC. Optical properties of InSb between 300 and 700 K. I. Temperature dependence of the energy gap. Phys Rev B Condens Matter 1993; 47:16274-16278. [PMID: 10006052 DOI: 10.1103/physrevb.47.16274] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [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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Zeitler U, Maan JC, Wyder P, Fletcher R, Foxon CT, Harris JJ. Investigation of the electron-phonon interaction in the fractional quantum Hall regime using the thermoelectric effect. Phys Rev B Condens Matter 1993; 47:16008-16011. [PMID: 10006013 DOI: 10.1103/physrevb.47.16008] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [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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Kutter C, Chitta V, Maan JC, Fal'ko VI, Leadbeater ML, Henini M, Eaves L. Tunneling spectroscopy of energy levels in wide quantum wells in tilted magnetic fields. Phys Rev B Condens Matter 1992; 45:8749-8751. [PMID: 10000718 DOI: 10.1103/physrevb.45.8749] [Citation(s) in RCA: 5] [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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Potemski M, Via L, Bauer GE, Maan JC, Ploog K, Weimann G. Magnetoexcitons in narrow GaAs/Ga1-xAlxAs quantum wells. Phys Rev B Condens Matter 1991; 43:14707-14710. [PMID: 9997365 DOI: 10.1103/physrevb.43.14707] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [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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Potemski M, Stepniewski R, Maan JC, Martinez G, Wyder P, Etienne B. Auger recombination within Landau levels in a two-dimensional electron gas. Phys Rev Lett 1991; 66:2239-2242. [PMID: 10043432 DOI: 10.1103/physrevlett.66.2239] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Toet D, Potemski M, Wang YY, Maan JC, Tapfer L, Ploog K. Experimental observation of Landau levels in nonperiodic (Fibonacci) superlattices. Phys Rev Lett 1991; 66:2128-2131. [PMID: 10043398 DOI: 10.1103/physrevlett.66.2128] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Cingolani R, Kalt H, Ploog K, Potemski M, Maan JC. Magnetoluminescence of the two-dimensional electron-hole fluid. Phys Rev B Condens Matter 1991; 43:9662-9671. [PMID: 9996664 DOI: 10.1103/physrevb.43.9662] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [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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Via L, Bauer GE, Potemski M, Maan JC, Mendez EE, Wang WI. Term spectrum of magnetoexcitons in quasi-two-dimensional systems. Phys Rev B Condens Matter 1990; 41:10767-10771. [PMID: 9993487 DOI: 10.1103/physrevb.41.10767] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [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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