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Kim SK, Nakata K, Loss D, Tserkovnyak Y. Tunable Magnonic Thermal Hall Effect in Skyrmion Crystal Phases of Ferrimagnets. PHYSICAL REVIEW LETTERS 2019; 122:057204. [PMID: 30822023 DOI: 10.1103/physrevlett.122.057204] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Indexed: 06/09/2023]
Abstract
We theoretically study the thermal Hall effect by magnons in skyrmion crystal phases of ferrimagnets in the vicinity of the angular momentum compensation point (CP). To this end, we start by deriving the equation of motion for magnons in the background of an arbitrary equilibrium spin texture, which gives rise to the fictitious electromagnetic field for magnons. As the net spin density varies, the resultant equation of motion interpolates between the relativistic Klein-Gordon equation at the CP and the nonrelativistic Schrödinger-like equation away from it. In skyrmion crystal phases, the right- and the left-circularly polarized magnons, with respect to the order parameter, are shown to form the Landau levels separately within the uniform skyrmion-density approximation. For an experimental proposal, we predict that the magnonic thermal Hall conductivity changes its sign when the ferrimagnet is tuned across the CP, providing a way to control heat flux in spin-caloritronic devices on the one hand and a feasible way to detect the CP of ferrimagnets on the other hand.
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Affiliation(s)
- Se Kwon Kim
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, USA
| | - Kouki Nakata
- Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan
| | - Daniel Loss
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
| | - Yaroslav Tserkovnyak
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
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Islamoğlu S, Oktel MO, Gülseren O. The integer quantum Hall effect of a square lattice with an array of point defects. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:345501. [PMID: 22850432 DOI: 10.1088/0953-8984/24/34/345501] [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
The electronic properties of a square lattice under an applied perpendicular magnetic field in the presence of impurities or vacancies are investigated by the tight-binding method including up to second nearest neighbor interactions. These imperfections result in new gaps and bands in the Hofstadter butterfly even when the second order interactions break the bipartite symmetry. In addition, the whole spectrum of the Hall conduction is obtained by the Kubo formula for the corresponding cases. The results are in accordance with the Thouless-Kohmoto-Nightingale-den Nijs integers when the Fermi energy lies in an energy gap. We find that the states due to the vacancies or impurities with small hopping constants are highly localized and do not contribute to the Hall conduction. However, the impurities with high hopping constants result in new Hall plateaus with constant conduction of σ(xy) =± e(2)/h, since high hopping constants increase the probability of an electron contributing to the conduction.
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Affiliation(s)
- S Islamoğlu
- Department of Physics, Bilkent University, 06800 Ankara, Turkey.
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Firoz Islam SK, Ghosh TK. Magnetotransport properties of a magnetically modulated two-dimensional electron gas with the spin-orbit interaction. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:185303. [PMID: 22481295 DOI: 10.1088/0953-8984/24/18/185303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We study the electrical transport properties of a two-dimensional electron gas (2DEG) with the Rashba spin-orbit interaction in the presence of a constant perpendicular magnetic field (B(0)( ̂z) which is weakly modulated by B1 = B1 cos(qx) ̂z, where B(1) ≪ B(0) and q = 2π/a with a the modulation period. We obtain the analytical expressions of the diffusive conductivities for spin-up and spin-down electrons. The conductivities for spin-up and spin-down electrons oscillate with different frequencies and produce beating patterns in the amplitude of the Weiss and Shubnikov-de Haas oscillations. We show that the Rashba strength can be determined by analyzing the beating pattern in the Weiss oscillation. We find a simple equation which determines the Rashba spin-orbit interaction strength if the number of Weiss oscillations between any two successive nodes is known from the experiment. We compare our results with the electrically modulated 2DEG with the Rashba interaction. For completeness, we also study the beating pattern formation in the collisional and the Hall conductivities.
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Affiliation(s)
- S K Firoz Islam
- Department of Physics, Indian Institute of Technology-Kanpur, Kanpur-208 016, India.
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Nasir R, Khan MA, Tahir M, Sabeeh K. Thermodynamic properties of a weakly modulated graphene monolayer in a magnetic field. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:025503. [PMID: 21386257 DOI: 10.1088/0953-8984/22/2/025503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Theoretical investigation of thermodynamic properties of an electrically modulated graphene monolayer in the presence of a perpendicular magnetic field B is presented. This work is aimed at determining the modulation-induced effects on the thermodynamic properties of graphene. The results obtained are compared with those of conventional two-dimensional electron gas (2DEG) systems realized in semiconductor heterostructures. The one-dimensional periodic potential, due to electric modulation lifts the degeneracy of the Landau levels and converts them into bands whose width oscillates as a function of B. We find commensurability (Weiss) oscillations for small values of B and de Haas-van Alphen (dHvA)-type oscillations at larger values of B. We find that the modulation-induced effects on the thermodynamic properties are enhanced and less damped with temperature in graphene compared with conventional 2DEG systems. Furthermore, we have derived analytic asymptotic expressions which allow us to determine the critical temperature and critical magnetic field for the damping of magnetic oscillations in the thermodynamic quantities considered here.
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Affiliation(s)
- R Nasir
- Department of Physics, Quaid-i-Azam University, Islamabad 45320, Pakistan
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Tahir M, Sabeeh K, MacKinnon A. The magnetoplasmon spectrum of a weakly modulated two-dimensional electron gas system. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:015801. [PMID: 21386234 DOI: 10.1088/0953-8984/22/1/015801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The magnetoplasmon spectrum of a magnetically modulated two-dimensional electron gas (2DEG) is investigated. We derive the inter- and intra-Landau-band magnetoplasmon spectrum within the self-consistent field approach. The derivation is performed at zero temperature as well as at finite temperature. Results are presented for the inter- and intra-Landau-band magnetoplasmon spectrum as a function of the inverse magnetic field. Magnetic Weiss oscillations are found to occur in the magnetoplasmon spectrum as a result of magnetic modulation. Furthermore, our finite temperature theory facilitates the analysis of effects of temperature on the magnetoplasmon spectrum. The results are compared with those obtained for an electrically modulated 2DEG system. In addition, we derive and discuss the effects of simultaneous electric and magnetic modulations on the magnetoplasmon spectrum of the 2DEG when the modulations are in phase as well as when they are out of phase. Magnetic oscillations are affected by the relative phase of the two modulations and the position of the oscillations depends on the relative strength of the two modulations in the former case while we find complete suppression of Weiss oscillations for a particular relative strength of the modulations in the latter case.
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Affiliation(s)
- M Tahir
- Department of Physics, Blackett Laboratory, Imperial College London, South Kensington Campus, London, UK.
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Ji ZL, Sprung DW. Electronic transport in quantum wires in nonuniform magnetic fields. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:8044-8048. [PMID: 9984482 DOI: 10.1103/physrevb.54.8044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Kim CS, Olendski O. Landau levels and persistent currents in nonuniform magnetic fields. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 53:12917-12928. [PMID: 9982966 DOI: 10.1103/physrevb.53.12917] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Shi QW, Szeto KY. Quantum transport theory of Weiss oscillations quenching of a two-dimensional electron gas in a strong periodic potential. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 53:12990-12993. [PMID: 9982975 DOI: 10.1103/physrevb.53.12990] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Gerhardts RR. Quasiclassical calculation of magnetoresistance oscillations of a two-dimensional electron gas in spatially periodic magnetic and electrostatic fields. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 53:11064-11075. [PMID: 9982679 DOI: 10.1103/physrevb.53.11064] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Gerhardts RR, Pfannkuche D, Gudmundsson V. Hofstadter-type energy spectra in lateral superlattices defined by periodic magnetic and electrostatic fields. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 53:9591-9594. [PMID: 9982508 DOI: 10.1103/physrevb.53.9591] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Oh GY, Lee MH. Energy spectrum of two-dimensional tight-binding electrons in a spatially varying magnetic field. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 53:1225-1230. [PMID: 9983579 DOI: 10.1103/physrevb.53.1225] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Ibrahim IS, Peeters FM. Two-dimensional electrons in lateral magnetic superlattices. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 52:17321-17334. [PMID: 9981162 DOI: 10.1103/physrevb.52.17321] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Gumbs G, Miessein D, Huang D. Effect of magnetic modulation on Bloch electrons on a two-dimensional square lattice. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 52:14755-14760. [PMID: 9980813 DOI: 10.1103/physrevb.52.14755] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Hedegård P, Smith A. Solution of the Boltzmann equation in a random magnetic field. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 51:10869-10874. [PMID: 9977783 DOI: 10.1103/physrevb.51.10869] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Carmona HA, Geim AK, Nogaret A, Main PC, Foster TJ, Henini M, Beaumont SP, Blamire MG. Two dimensional electrons in a lateral magnetic superlattice. PHYSICAL REVIEW LETTERS 1995; 74:3009-3012. [PMID: 10058080 DOI: 10.1103/physrevlett.74.3009] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Ye PD, Weiss D, Gerhardts RR, Seeger M, Eberl K, Nickel H. Electrons in a periodic magnetic field induced by a regular array of micromagnets. PHYSICAL REVIEW LETTERS 1995; 74:3013-3016. [PMID: 10058081 DOI: 10.1103/physrevlett.74.3013] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Chang MC, Niu Q. Electron band structure in a two-dimensional periodic magnetic field. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 50:10843-10850. [PMID: 9975185 DOI: 10.1103/physrevb.50.10843] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Huang D, Gumbs G, Horing NJ. Magneto-optical absorption in a one-dimensional array of narrow antiwires. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 49:11463-11466. [PMID: 10010005 DOI: 10.1103/physrevb.49.11463] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Tan Y. Quantum magnetotransport of a periodically modulated two-dimensional electron gas. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 49:1827-1835. [PMID: 10010978 DOI: 10.1103/physrevb.49.1827] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Brey L, Fertig HA. Hall resistance of a two-dimensional electron gas in the presence of magnetic-flux tubes. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 47:15961-15964. [PMID: 10006001 DOI: 10.1103/physrevb.47.15961] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Wu X, Ulloa SE. Collective excitations of a two-dimensional electron gas in a two-dimensional magnetic-field modulation. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 47:10028-10031. [PMID: 10005102 DOI: 10.1103/physrevb.47.10028] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Wu X, Ulloa SE. Electronic states and collective excitations of a two-dimensional electron gas in a unidirectional magnetic-field modulation. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 47:7182-7186. [PMID: 10004715 DOI: 10.1103/physrevb.47.7182] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Peeters FM, Vasilopoulos P. Quantum transport of a two-dimensional electron gas in a spatially modulated magnetic field. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 47:1466-1473. [PMID: 10006161 DOI: 10.1103/physrevb.47.1466] [Citation(s) in RCA: 83] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Pfannkuche D, Gerhardts RR. Theory of magnetotransport in two-dimensional electron systems subjected to weak two-dimensional superlattice potentials. PHYSICAL REVIEW. B, CONDENSED MATTER 1992; 46:12606-12626. [PMID: 10003180 DOI: 10.1103/physrevb.46.12606] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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