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Kumar AS, Liu CW, Liu S, Gao XPA, Levchenko A, Pfeiffer LN, West KW. Anomalous High-Temperature Magnetoresistance in a Dilute 2D Hole System. PHYSICAL REVIEW LETTERS 2023; 130:266302. [PMID: 37450788 DOI: 10.1103/physrevlett.130.266302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 08/15/2022] [Accepted: 06/02/2023] [Indexed: 07/18/2023]
Abstract
We report an unusual magnetoresistance that strengthens with the temperature in a dilute two-dimensional (2D) hole system in GaAs/AlGaAs quantum wells with densities p=1.98-0.99×10^{10}/cm^{2} where r_{s}, the ratio between Coulomb energy and Fermi energy, is as large as 20-30. We show that, while the system exhibits a negative parabolic magnetoresistance at low temperatures (≲0.4 K) characteristic of an interacting Fermi liquid, a positive magnetoresistance emerges unexpectedly at higher temperatures, and grows with increasing temperature even in the regime T∼E_{F}, close to the Fermi energy. This unusual positive magnetoresistance at high temperatures can be attributed to the viscous transport of 2D hole fluid in the hydrodynamic regime where holes scatter frequently with each other. These findings give insight into the collective transport of strongly interacting carriers in the r_{s}≫1 regime and new routes toward magnetoresistance at high temperatures.
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Affiliation(s)
- Arvind Shankar Kumar
- Department of Physics, Case Western Reserve University, 2076 Adelbert Road, Cleveland, Ohio 44106, USA
| | - Chieh-Wen Liu
- Department of Physics, Case Western Reserve University, 2076 Adelbert Road, Cleveland, Ohio 44106, USA
| | - Shuhao Liu
- Department of Physics, Case Western Reserve University, 2076 Adelbert Road, Cleveland, Ohio 44106, USA
| | - Xuan P A Gao
- Department of Physics, Case Western Reserve University, 2076 Adelbert Road, Cleveland, Ohio 44106, USA
| | - Alex Levchenko
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Loren N Pfeiffer
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Kenneth W West
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
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2
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Jeong K, Park H, Chae J, Sim KI, Yang WJ, Kim JH, Hong SB, Kim JH, Cho MH. Topological Phase Control of Surface States in Bi 2Se 3 via Spin-Orbit Coupling Modulation through Interface Engineering between HfO 2-X. ACS APPLIED MATERIALS & INTERFACES 2020; 12:12215-12226. [PMID: 32073823 DOI: 10.1021/acsami.9b17555] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The direct control of topological surface states in topological insulators is an important prerequisite for the application of these materials. Conventional attempts to utilize magnetic doping, mechanical tuning, structural engineering, external bias, and external magnetic fields suffer from a lack of reversible switching and have limited tunability. We demonstrate the direct control of topological phases in a bismuth selenide (Bi2Se3) topological insulator in 3 nm molecular beam epitaxy-grown films through the hybridization of the topological surface states with the hafnium (Hf) d-orbitals in the topmost layer of an underlying oxygen-deficient hafnium oxide (HfO2) substrate. The higher angular momentum of the d-orbitals of Hf is hybridized strongly by topological insulators, thereby enhancing the spin-orbit coupling and perturbing the topological surface states asymmetry in Bi2Se3. As the oxygen defect is cured or generated reversibly by external electric fields, our research facilitates the complete electrical control of the topological phases of topological insulators by controlling the defect density in the adjacent transition metal oxide. In addition, this mechanism can be applied in other related topological materials such as Weyl and Dirac semimetals in future endeavors to facilitate practical applications in unit-element devices for quantum computing and quantum communication.
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Affiliation(s)
- Kwangsik Jeong
- Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749, Republic of Korea
| | - Hanbum Park
- Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749, Republic of Korea
| | - Jimin Chae
- Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749, Republic of Korea
| | - Kyung-Ik Sim
- Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749, Republic of Korea
| | - Won Jun Yang
- Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749, Republic of Korea
| | - Jong-Hoon Kim
- Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749, Republic of Korea
| | - Seok-Bo Hong
- Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749, Republic of Korea
| | - Jae Hoon Kim
- Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749, Republic of Korea
| | - Mann-Ho Cho
- Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749, Republic of Korea
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Wang Z, Samaraweera RL, Reichl C, Wegscheider W, Mani RG. Tunable electron heating induced giant magnetoresistance in the high mobility GaAs/AlGaAs 2D electron system. Sci Rep 2016; 6:38516. [PMID: 27924953 PMCID: PMC5141424 DOI: 10.1038/srep38516] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 11/10/2016] [Indexed: 11/25/2022] Open
Abstract
Electron-heating induced by a tunable, supplementary dc-current (Idc) helps to vary the observed magnetoresistance in the high mobility GaAs/AlGaAs 2D electron system. The magnetoresistance at B = 0.3 T is shown to progressively change from positive to negative with increasing Idc, yielding negative giant-magnetoresistance at the lowest temperature and highest Idc. A two-term Drude model successfully fits the data at all Idc and T. The results indicate that carrier heating modifies a conductivity correction σ1, which undergoes sign reversal from positive to negative with increasing Idc, and this is responsible for the observed crossover from positive- to negative- magnetoresistance, respectively, at the highest B.
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Affiliation(s)
- Zhuo Wang
- Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303, USA
| | - R L Samaraweera
- Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303, USA
| | - C Reichl
- Laboratorium für Festkörperphysik, ETH-Zürich, Zürich 8093, Switzerland
| | - W Wegscheider
- Laboratorium für Festkörperphysik, ETH-Zürich, Zürich 8093, Switzerland
| | - R G Mani
- Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303, USA
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4
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Shamim S, Mahapatra S, Scappucci G, Klesse WM, Simmons MY, Ghosh A. Spontaneous breaking of time-reversal symmetry in strongly interacting two-dimensional electron layers in silicon and germanium. PHYSICAL REVIEW LETTERS 2014; 112:236602. [PMID: 24972220 DOI: 10.1103/physrevlett.112.236602] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Indexed: 06/03/2023]
Abstract
We report experimental evidence of a remarkable spontaneous time-reversal symmetry breaking in two-dimensional electron systems formed by atomically confined doping of phosphorus (P) atoms inside bulk crystalline silicon (Si) and germanium (Ge). Weak localization corrections to the conductivity and the universal conductance fluctuations were both found to decrease rapidly with decreasing doping in the Si:P and Ge:P delta layers, suggesting an effect driven by Coulomb interactions. In-plane magnetotransport measurements indicate the presence of intrinsic local spin fluctuations at low doping, providing a microscopic mechanism for spontaneous lifting of the time-reversal symmetry. Our experiments suggest the emergence of a new many-body quantum state when two-dimensional electrons are confined to narrow half-filled impurity bands.
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Affiliation(s)
- S Shamim
- Department of Physics, Indian Institute of Science, Bangalore 560 012, India
| | - S Mahapatra
- Centre for Quantum Computation and Communication Technology, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - G Scappucci
- Centre for Quantum Computation and Communication Technology, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - W M Klesse
- Centre for Quantum Computation and Communication Technology, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - M Y Simmons
- Centre for Quantum Computation and Communication Technology, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - A Ghosh
- Department of Physics, Indian Institute of Science, Bangalore 560 012, India
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Mani RG, Kriisa A, Wegscheider W. Size-dependent giant-magnetoresistance in millimeter scale GaAs/AlGaAs 2D electron devices. Sci Rep 2013; 3:2747. [PMID: 24067264 PMCID: PMC3782888 DOI: 10.1038/srep02747] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 09/04/2013] [Indexed: 11/09/2022] Open
Abstract
Large changes in the electrical resistance induced by the application of a small magnetic field are potentially useful for device-applications. Such Giant Magneto-Resistance (GMR) effects also provide new insights into the physical phenomena involved in the associated electronic transport. This study examines a "bell-shape" negative GMR that grows in magnitude with decreasing temperatures in mm-wide devices fabricated from the high-mobility GaAs/AlGaAs 2-Dimensional Electron System (2DES). Experiments show that the span of this magnetoresistance on the magnetic-field-axis increases with decreasing device width, W, while there is no concurrent Hall resistance, Rxy, correction. A multi-conduction model, including negative diagonal-conductivity, and non-vanishing off-diagonal conductivity, reproduces experimental observations. The results suggest that a size effect in the mm-wide 2DES with mm-scale electron mean-free-paths is responsible for the observed "non-ohmic" size-dependent negative GMR.
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Affiliation(s)
- R G Mani
- Dept. of Physics and Astronomy, Georgia State University, Atlanta, GA 30303 U.S.A
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Bockhorn L, Hodaei A, Schuh D, Wegscheider W, Haug RJ. Magnetoresistance in a High Mobility Two-Dimensional Electron System as a Function of Sample Geometry. ACTA ACUST UNITED AC 2013. [DOI: 10.1088/1742-6596/456/1/012003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Lo ST, Wang YT, Lin SD, Strasser G, Bird JP, Chen YF, Liang CT. Tunable insulator-quantum Hall transition in a weakly interacting two-dimensional electron system. NANOSCALE RESEARCH LETTERS 2013; 8:307. [PMID: 23819745 PMCID: PMC3716820 DOI: 10.1186/1556-276x-8-307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 06/26/2013] [Indexed: 06/02/2023]
Abstract
We have performed low-temperature measurements on a gated two-dimensional electron system in which electron-electron (e-e) interactions are insignificant. At low magnetic fields, disorder-driven movement of the crossing of longitudinal and Hall resistivities (ρxx and ρxy) can be observed. Interestingly, by applying different gate voltages, we demonstrate that such a crossing at ρxx ~ ρxy can occur at a magnetic field higher, lower, or equal to the temperature-independent point in ρxx which corresponds to the direct insulator-quantum Hall transition. We explicitly show that ρxx ~ ρxy occurs at the inverse of the classical Drude mobility 1/μD rather than the crossing field corresponding to the insulator-quantum Hall transition. Moreover, we show that the background magnetoresistance can affect the transport properties of our device significantly. Thus, we suggest that great care must be taken when calculating the renormalized mobility caused by e-e interactions.
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Affiliation(s)
- Shun-Tsung Lo
- Graduate Institute of Applied Physics, National Taiwan University, Taipei 106, Taiwan
| | - Yi-Ting Wang
- Department of Physics, National Taiwan University, Taipei 106, Taiwan
| | - Sheng-Di Lin
- Department of Electronics Engineering, National Chiao Tung University, Hsinchu 300, Taiwan
| | - Gottfried Strasser
- Institute for Solid State Electronics and Center for Micro- and Nanostructures, Technische Universität Wien, Floragasse 7, 1040, Vienna, Austria
| | - Jonathan P Bird
- Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260-1920, USA
| | - Yang-Fang Chen
- Graduate Institute of Applied Physics, National Taiwan University, Taipei 106, Taiwan
- Department of Physics, National Taiwan University, Taipei 106, Taiwan
| | - Chi-Te Liang
- Graduate Institute of Applied Physics, National Taiwan University, Taipei 106, Taiwan
- Department of Physics, National Taiwan University, Taipei 106, Taiwan
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Li L, Wang J, Kim GH, Ritchie DA. Electron dephasing of a GaAs/AlGaAs quantum well with self-assembled InAs dots. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:385301. [PMID: 22945470 DOI: 10.1088/0953-8984/24/38/385301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We study the magnetotransport of a GaAs/AlGaAs quantum well with self-assembled InAs quantum dots. Negative magnetoresistance is observed at low field and analysed by weak localization theory. The temperature dependence of the extracted dephasing rate is linear, which shows that the inelastic electron-electron scattering processes with small energy transfer are the dominant contribution in breaking the electron phase coherence. The results are compared with those of a reference sample that contains no quantum dots.
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Affiliation(s)
- L Li
- School of Electronic and Electrical Engineering and Sungkyunkwan University Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon, Republic of Korea
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Jobst J, Waldmann D, Gornyi IV, Mirlin AD, Weber HB. Electron-electron interaction in the magnetoresistance of graphene. PHYSICAL REVIEW LETTERS 2012; 108:106601. [PMID: 22463434 DOI: 10.1103/physrevlett.108.106601] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Indexed: 05/31/2023]
Abstract
We investigate the magnetotransport in large area graphene Hall bars epitaxially grown on silicon carbide. In the intermediate field regime between weak localization and Landau quantization, the observed temperature-dependent parabolic magnetoresistivity is a manifestation of the electron-electron interaction. We can consistently describe the data with a model for diffusive (magneto)transport that also includes magnetic-field-dependent effects originating from ballistic time scales. We find an excellent agreement between the experimentally observed temperature dependence of magnetoresistivity and the theory of electron-electron interaction in the diffusive regime. We can further assign a temperature-driven crossover to the reduction of the multiplet modes contributing to electron-electron interaction from 7 to 3 due to intervalley scattering. In addition, we find a temperature-independent ballistic contribution to the magnetoresistivity in classically strong magnetic fields.
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Affiliation(s)
- Johannes Jobst
- Lehrstuhl für Angewandte Physik, Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
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10
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Renard VT, Tkachenko OA, Tkachenko VA, Ota T, Kumada N, Portal JC, Hirayama Y. Boundary-mediated electron-electron interactions in quantum point contacts. PHYSICAL REVIEW LETTERS 2008; 100:186801. [PMID: 18518401 DOI: 10.1103/physrevlett.100.186801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2007] [Indexed: 05/26/2023]
Abstract
An unusual increase of the conductance with temperature is observed in clean quantum point contacts for conductances larger than 2(e2/h). At the same time, a positive magnetoresistance arises at high temperatures. A model accounting for electron-electron interactions mediated by boundaries (scattering on Friedel oscillations) qualitatively describes the observation. It is supported by a numerical simulation at zero magnetic field.
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Affiliation(s)
- V T Renard
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi 243-0198, Japan
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Sedrakyan TA, Raikh ME. Crossover from weak localization to Shubnikov-de Haas oscillations in a high-mobility 2D electron gas. PHYSICAL REVIEW LETTERS 2008; 100:106806. [PMID: 18352222 DOI: 10.1103/physrevlett.100.106806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2007] [Indexed: 05/26/2023]
Abstract
We study the magnetoresistance deltarho(xx)(B)/rho(0) of a high-mobility 2D electron gas in the domain of magnetic fields B, intermediate between the weak localization and the Shubnikov-de Haas oscillations, where deltarho(xx)(B)/rho(0) is governed by the interaction effects. Assuming short-range impurity scattering, we demonstrate that in the second order in the interaction parameter lambda a linear B dependence, deltarho(xx)(B)/rho(0) approximately lambda(2)omega(c)/E(F) with a temperature-independent slope, emerges in this domain of B (here omega(c) and E(F) are the cyclotron frequency and the Fermi energy, respectively). Unlike previous mechanisms, the linear magnetoresistance is unrelated to the electron executing the full Larmour circle, but rather originates from the impurity scattering via the B dependence of the phase of the impurity-induced Friedel oscillations.
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Affiliation(s)
- T A Sedrakyan
- Department of Physics, University of Utah, Salt Lake City, Utah 84112, USA
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Sedrakyan TA, Mishchenko EG, Raikh ME. Smearing of the two-dimensional Kohn anomaly in a nonquantizing magnetic field: implications for interaction effects. PHYSICAL REVIEW LETTERS 2007; 99:036401. [PMID: 17678299 DOI: 10.1103/physrevlett.99.036401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2006] [Indexed: 05/16/2023]
Abstract
Thermodynamic and transport characteristics of a clean two-dimensional interacting electron gas are shown to be sensitive to the weak perpendicular magnetic field even at temperatures much higher than the cyclotron energy, when the quantum oscillations are completely washed out. We demonstrate this sensitivity for two interaction-related characteristics: electron lifetime and the tunnel density of states. The origin of the sensitivity is traced to the field-induced smearing of the Kohn anomaly; this smearing is the result of curving of the semiclassical electron trajectories in magnetic field.
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Affiliation(s)
- T A Sedrakyan
- Department of Physics, University of Utah, Salt Lake City, Utah 84112, USA
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Gao XPA, Boebinger GS, Mills AP, Ramirez AP, Pfeiffer LN, West KW. Temperature and magnetic-field-enhanced hall slope of a dilute 2D hole system in the ballistic regime. PHYSICAL REVIEW LETTERS 2004; 93:256402. [PMID: 15697919 DOI: 10.1103/physrevlett.93.256402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2004] [Indexed: 05/24/2023]
Abstract
We report the temperature (T) and perpendicular magnetic-field (B) dependence of the Hall resistivity rho(xy)(B) of dilute metallic 2D holes in GaAs over a broad range of temperature (0.02-1.25 K). The low B Hall coefficient, R(H), is found to be enhanced when T decreases. Strong magnetic fields further enhance the slope of rho(xy)(B) at all temperatures studied. Coulomb interaction corrections of a Fermi liquid (FL) in the ballistic regime can not explain the enhancement of rho(xy) which occurs in the same regime as the anomalous metallic longitudinal conductivity. In particular, although the metallic conductivity in 2D systems has been attributed to electron interactions in a FL, these same interactions should reduce, not enhance, the slope of rho(xy)(B) as T decreases and/or B increases.
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Affiliation(s)
- X P A Gao
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
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Li L, Proskuryakov YY, Savchenko AK, Linfield EH, Ritchie DA. Magnetoresistance of a 2D electron gas caused by electron interactions in the transition from the diffusive to the ballistic regime. PHYSICAL REVIEW LETTERS 2003; 90:076802. [PMID: 12633258 DOI: 10.1103/physrevlett.90.076802] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2002] [Indexed: 05/24/2023]
Abstract
On a high-mobility 2D electron gas we have observed, in strong magnetic fields (omega(c)tau>1), a parabolic negative magnetoresistance caused by electron-electron interactions in the regime of k(B)Ttau/ variant Planck's over 2pi approximately 1, which is the transition from the diffusive to the ballistic regime. From the temperature dependence of this magnetoresistance the interaction correction to the conductivity deltasigma(ee)(xx)(T) is obtained in the situation of a long-range fluctuation potential and strong magnetic field. The results are compared with predictions of the new theory of interaction-induced magnetoresistance.
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Affiliation(s)
- L Li
- School of Physics, University of Exeter, Stocker Road, Exeter, EX4 4QL, United Kingdom
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