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Periáñez R, Brovchenko I, Jung KT, Kim KO, Liptak L, Little A, Kobayashi T, Maderich V, Min BI, Suh KS. Some considerations on the dependence to numerical schemes of Lagrangian radionuclide transport models for the aquatic environment. J Environ Radioact 2023; 261:107138. [PMID: 36841197 DOI: 10.1016/j.jenvrad.2023.107138] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 02/10/2023] [Accepted: 02/11/2023] [Indexed: 06/18/2023]
Abstract
Lagrangian models present several advantages over Eulerian models to simulate the transport of radionuclides in the aquatic environment in emergency situations. A radionuclide release is simulated as a number of particles whose trajectories are calculated along time and thus these models do not require a spatial discretization (although it is always required in time). In this paper we investigate the dependence of a Lagrangian model output with the grid spacing which is used to calculate concentrations from the final distribution of particles, with the number of particles in the simulation and with the interpolation schemes which are required because of the discrete nature of the water circulation data used to feed the model. Also, a Lagrangian model may describe the exchanges of radionuclides between phases (liquid and solid), which is done in terms of transition probabilities. The dependence of these probabilities with time step is analyzed as well. It was found that the optimum grid size used to calculate concentrations should be carefully checked, and that temporal interpolation is more significant than spatial interpolation to obtain a more accurate solution. A method to estimate the number of particles required to have a certain accuracy level is proposed. Finally, it was found that for low sediment concentrations and small radionuclide kd, exact equations for the transition probabilities should be used; and that phase transitions introduce a stability condition as in Eulerian models.
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Affiliation(s)
- R Periáñez
- Dpt Física Aplicada I, ETSIA Universidad de Sevilla, Ctra Utrera km 1, 41013-Sevilla, Spain.
| | - I Brovchenko
- Institute of Mathematical Machine and System Problems, Glushkov av., 42, Kiev 03187, Ukraine
| | - K T Jung
- Environmental Research Institute of Oceanic Co. Ltd., 403 Munlnva-Building, 90 Yangpyung-ro, Yeongdeungpo-gu, Seoul, Republic of Korea
| | - K O Kim
- Korea Institute of Ocean Science and Technology, 385, Haeyang-ro, Yeongdo-gu, Busan Metropolitan City, Republic of Korea
| | - L Liptak
- AB Merit s.r.o., Hornopotocna 1, 917 01 Trnava, Slovakia
| | - A Little
- Defence Academy of the United Kingdom, HMS Sultan, Military Road Gosport, Hampshire P012 3BY, UK
| | - T Kobayashi
- Japan Atomic Energy Agency, 2-4 Shirakata Shirane, Tokai, Ibaraki 319-1195, Japan
| | - V Maderich
- Institute of Mathematical Machine and System Problems, Glushkov av., 42, Kiev 03187, Ukraine
| | - B I Min
- Korea Atomic Energy Research Institute, Daedeok-Daero 989-111, Yuseong-Gu, Daejeon, Republic of Korea
| | - K S Suh
- Korea Atomic Energy Research Institute, Daedeok-Daero 989-111, Yuseong-Gu, Daejeon, Republic of Korea
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Kang CJ, Kim K, Min BI. Band theoretical approaches to topological physics in strongly-correlated f-electron Kondo systems. J Phys Condens Matter 2022; 34:271501. [PMID: 35073534 DOI: 10.1088/1361-648x/ac4e47] [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: 10/07/2021] [Accepted: 01/24/2022] [Indexed: 06/14/2023]
Abstract
First-principles band structure theory on the basis of the density functional theory (DFT) plays an essential role in the investigation of topological properties of weakly-correlated systems. DFT band structures show clear bulk band crossings for Weyl and Dirac semimetals, and surface band crossings for topological insulators and topological-crystalline insulators. In contrast, for strongly-correlatedf-electron systems, their topological properties are relatively less explored because the simple DFT does not work properly in describing the electronic structures of strongly-correlatedfelectrons. In this perspective, we examine the band theoretical approaches to topological properties of strongly-correlatedf-electron Kondo systems. We recapitulate current status of understanding of electronic structures and topological properties of strongly-correlated 4f-electron systems, such as Ce, SmB6, and g-SmS, and also a 5f-electron system PuB4, the electronic structures of which were investigated by the DFT combined with the dynamical mean-field theory (DFT + DMFT). Finally, we provide future directions and perspectives of improving theoretical band approaches to search for new topologicalf-electron systems, as an outlook.
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Affiliation(s)
- Chang-Jong Kang
- Department of Physics, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Kyoo Kim
- Korea Atomic Energy Research Institute (KAERI), 111 Daedeok-daero, Daejeon 34057, Republic of Korea
| | - B I Min
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
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3
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Periáñez R, Min BI, Suh KS. The transport, effective half-lives and age distributions of radioactive releases in the northern Indian Ocean. Mar Pollut Bull 2021; 169:112587. [PMID: 34111607 DOI: 10.1016/j.marpolbul.2021.112587] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 05/26/2021] [Accepted: 05/27/2021] [Indexed: 06/12/2023]
Abstract
A Lagrangian model which describes radionuclide transport in the northern Indian Ocean is described. Water circulation is obtained from HYCOM ocean model for year 2017. The model includes advection by currents, turbulent mixing and radionuclide interactions between water and sediments, described in a dynamic way using kinetic transfer coefficients. Hypothetical releases from five coastal nuclear power plants operating in the northern Indian Ocean were simulated. Releases were supposed to start both during the winter and summer monsoons, to study reversing circulation effects. Age distributions of releases were calculated, which adds information about circulation and radionuclide pathways. It was found that, for some of the NPPs, radionuclide distributions resulting from releases starting in both seasons were not as different as could be expected from the opposed circulation schemes during each monsoon. Effective 137Cs half-lives in the ocean surface were calculated and results were two orders of magnitude below previous estimations.
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Affiliation(s)
- R Periáñez
- Dpt Física Aplicada I, ETSIA, Universidad de Sevilla, Ctra Utrera km 1, 41013 Sevilla, Spain.
| | - B I Min
- Korea Atomic Research Institute, Daedeok-Daero 989-111, Yuseong-Gu, Daejeon, Republic of Korea
| | - K S Suh
- Korea Atomic Research Institute, Daedeok-Daero 989-111, Yuseong-Gu, Daejeon, Republic of Korea
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4
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Kim H, Shim JH, Kim S, Park JH, Kim K, Min BI. Unusual Pressure-Induced Quantum Phase Transition from Superconducting to Charge-Density Wave State in Rare-Earth-Based Heusler LuPd_{2}In Compound. Phys Rev Lett 2020; 125:157001. [PMID: 33095605 DOI: 10.1103/physrevlett.125.157001] [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: 07/29/2019] [Revised: 03/10/2020] [Accepted: 09/10/2020] [Indexed: 06/11/2023]
Abstract
We investigate the pressure effects on the electronic structures and phonon properties of rare-earth-based cubic-Heusler compound LuPd_{2}In, on the basis of ab initio density functional theory. We find the occurrence of intriguing phase transition from the superconducting (SC) to charge-density wave (CDW) state under pressure (P), which is quite unusual in that the pressure is detrimental to the CDW state in usual systems. The SC transition temperature T_{C} of LuPd_{2}In increases first with increasing pressure, up to P_{C}≈28 GPa, above which a quantum phase transition into the CDW state takes place. This extraordinary transition originates from the occurrence of phonon softening instability at a special q=M in the Brillouin zone. We thus propose that LuPd_{2}In is a quite unique material, in which the CDW quantum critical point is realized under the SC dome by applying the pressure.
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Affiliation(s)
- Heejung Kim
- Department of Physics, POSTECH, Pohang 37673, Korea
- MPPHC-CPM, Max Planck POSTECH/Korea Research Initiative, Pohang 37673, Korea
| | - J H Shim
- Department of Physics, POSTECH, Pohang 37673, Korea
- Department of Chemistry, POSTECH, Pohang 37673, Korea
| | - Sooran Kim
- Department of Physics Education, Kyungpook National University, Daegu 41566, Korea
| | - Jae-Hoon Park
- Department of Physics, POSTECH, Pohang 37673, Korea
- MPPHC-CPM, Max Planck POSTECH/Korea Research Initiative, Pohang 37673, Korea
- Division of Advanced Materials Science, POSTECH, Pohang 37673, Korea
| | - Kyoo Kim
- Department of Physics, POSTECH, Pohang 37673, Korea
- MPPHC-CPM, Max Planck POSTECH/Korea Research Initiative, Pohang 37673, Korea
- Korea Atomic Energy Research Institute (KAERI), 111 Daedeok-daero, Daejeon 34057, Korea
| | - B I Min
- Department of Physics, POSTECH, Pohang 37673, Korea
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Periáñez R, Bezhenar R, Brovchenko I, Jung KT, Kamidara Y, Kim KO, Kobayashi T, Liptak L, Maderich V, Min BI, Suh KS. Fukushima 137Cs releases dispersion modelling over the Pacific Ocean. Comparisons of models with water, sediment and biota data. J Environ Radioact 2019; 198:50-63. [PMID: 30590333 DOI: 10.1016/j.jenvrad.2018.12.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 12/14/2018] [Accepted: 12/14/2018] [Indexed: 06/09/2023]
Abstract
A number of marine radionuclide dispersion models (both Eulerian and Lagrangian) were applied to simulate 137Cs releases from Fukushima Daiichi nuclear power plant accident in 2011 over the Pacific at oceanic scale. Simulations extended over two years and both direct releases into the ocean and deposition of atmospheric releases on the ocean surface were considered. Dispersion models included an embedded biological uptake model (BUM). Three types of BUMs were used: equilibrium, dynamic and allometric. Model results were compared with 137Cs measurements in water (surface, intermediate and deep layers), sediment and biota (zooplankton, non-piscivorous and piscivorous fish). A reasonable agreement in model/model and model/data comparisons was obtained.
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Affiliation(s)
- R Periáñez
- Dpt Física Aplicada I, ETSIA, Universidad de Sevilla, Ctra Utrera km 1, 41013, Sevilla, Spain.
| | - R Bezhenar
- Institute of Mathematical Machine and System Problems, Glushkov av., 42, Kiev, 03187, Ukraine
| | - I Brovchenko
- Institute of Mathematical Machine and System Problems, Glushkov av., 42, Kiev, 03187, Ukraine
| | - K T Jung
- Korea Institute of Ocean Science and Technology, 385, Haeyang-ro, Yeongdo-gu, Busan Metropolitan City, Republic of Korea
| | - Y Kamidara
- Japan Atomic Energy Agency, 2-4 Shirakata Shirane, Tokai, Ibaraki, 319-1195, Japan
| | - K O Kim
- Korea Institute of Ocean Science and Technology, 385, Haeyang-ro, Yeongdo-gu, Busan Metropolitan City, Republic of Korea
| | - T Kobayashi
- Japan Atomic Energy Agency, 2-4 Shirakata Shirane, Tokai, Ibaraki, 319-1195, Japan
| | - L Liptak
- ABmerit s.r.o., Hornopotocna 1, 917 01, Trnava, Slovakia
| | - V Maderich
- Institute of Mathematical Machine and System Problems, Glushkov av., 42, Kiev, 03187, Ukraine
| | - B I Min
- Korea Atomic Energy Research Institute, Daedeok-Daero, 989-111, Yuseong-Gu, Daejeon, Republic of Korea
| | - K S Suh
- Korea Atomic Energy Research Institute, Daedeok-Daero, 989-111, Yuseong-Gu, Daejeon, Republic of Korea
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Noh HJ, Jeong J, Cho EJ, Kim K, Min BI, Park BG. Experimental Realization of Type-II Dirac Fermions in a PdTe_{2} Superconductor. Phys Rev Lett 2017; 119:016401. [PMID: 28731733 DOI: 10.1103/physrevlett.119.016401] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Indexed: 05/12/2023]
Abstract
A Dirac fermion in a topological Dirac semimetal is a quadruple-degenerate quasiparticle state with a relativistic linear dispersion. Breaking either time-reversal or inversion symmetry turns this system into a Weyl semimetal that hosts double-degenerate Weyl fermion states with opposite chiralities. These two kinds of quasiparticles, although described by a relativistic Dirac equation, do not necessarily obey Lorentz invariance, allowing the existence of so-called type-II fermions. The recent theoretical discovery of type-II Weyl fermions evokes the prediction of type-II Dirac fermions in PtSe_{2}-type transition metal dichalcogenides, expecting experimental confirmation. Here, we report an experimental realization of type-II Dirac fermions in PdTe_{2} by angle-resolved photoemission spectroscopy combined with ab initio band calculations. Our experimental finding shows the first example that has both superconductivity and type-II Dirac fermions, which turns the topological material research into a new phase.
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Affiliation(s)
- Han-Jin Noh
- Department of Physics, Chonnam National University, Gwangju 61186, Korea
| | - Jinwon Jeong
- Department of Physics, Chonnam National University, Gwangju 61186, Korea
| | - En-Jin Cho
- Department of Physics, Chonnam National University, Gwangju 61186, Korea
| | - Kyoo Kim
- MPPC_CPM, Pohang University of Science and Technology, Pohang 37673, Korea
| | - B I Min
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Byeong-Gyu Park
- Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang 37673, Korea
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7
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Periáñez R, Bezhenar R, Brovchenko I, Duffa C, Iosjpe M, Jung KT, Kobayashi T, Lamego F, Maderich V, Min BI, Nies H, Osvath I, Outola I, Psaltaki M, Suh KS, de With G. Modelling of marine radionuclide dispersion in IAEA MODARIA program: Lessons learnt from the Baltic Sea and Fukushima scenarios. Sci Total Environ 2016; 569-570:594-602. [PMID: 27376914 DOI: 10.1016/j.scitotenv.2016.06.131] [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] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 06/16/2016] [Accepted: 06/17/2016] [Indexed: 06/06/2023]
Abstract
State-of-the art dispersion models were applied to simulate (137)Cs dispersion from Chernobyl nuclear power plant disaster fallout in the Baltic Sea and from Fukushima Daiichi nuclear plant releases in the Pacific Ocean after the 2011 tsunami. Models were of different nature, from box to full three-dimensional models, and included water/sediment interactions. Agreement between models was very good in the Baltic. In the case of Fukushima, results from models could be considered to be in acceptable agreement only after a model harmonization process consisting of using exactly the same forcing (water circulation and parameters) in all models. It was found that the dynamics of the considered system (magnitude and variability of currents) was essential in obtaining a good agreement between models. The difficulties in developing operative models for decision-making support in these dynamic environments were highlighted. Three stages which should be considered after an emergency, each of them requiring specific modelling approaches, have been defined. They are the emergency, the post-emergency and the long-term phases.
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Affiliation(s)
- R Periáñez
- Dpt Física Aplicada I, ETSIA, Universidad de Sevilla, Ctra Utrera km 1, 41013-Sevilla, Spain.
| | - R Bezhenar
- Ukrainian Center of Environmental and Water Projects, Glushkov av., 42, Kiev 03187, Ukraine
| | - I Brovchenko
- Institute of Mathematical Machine and System Problems, Glushkov av., 42, Kiev 03187, Ukraine
| | - C Duffa
- Institut de Radioprotection et de Sûreté Nucléaire, BP 330, 83507 La Seyne sur Mer, France
| | - M Iosjpe
- Norwegian Radiation Protection Authority, Grini næringspark 13, NO-1332, Østerås, Norway
| | - K T Jung
- Korea Institute of Ocean Science and Technology, 787 Hean-ro, Sangnok-gu, Ansan-si, Gyeonggi-do, 426-744, Republic of Korea
| | - T Kobayashi
- Japan Atomic Energy Agency, 2-4 Shirakata Shirane, Tokai, Ibaraki 319-1195, Japan
| | - F Lamego
- Instituto de Engenheria Nuclear, Rua Hélio de Almeida 75, Ilha do Fundão, CEP 21941-906 Rio de Janeiro, Brazil
| | - V Maderich
- Institute of Mathematical Machine and System Problems, Glushkov av., 42, Kiev 03187, Ukraine
| | - B I Min
- Korea Atomic Energy Research Institute, Daedeok-Daero 989-111, Yuseong-Gu, Daejeon, Republic of Korea
| | - H Nies
- Bundesamt fuer Seeschifffahrt und Hydrographie, Bernhard-Nocht-Str. 78, 20359 Hamburg, Germany
| | - I Osvath
- International Atomic Energy Agency Environment Laboratories, 4a Quai Antoine 1er, MC-98000, Monaco
| | - I Outola
- Radiation and Nuclear Safety Authority, Laippatie 4, 00880 Helsinki, Finland
| | - M Psaltaki
- National Technical University of Athens, Iroon Polytexneiou 9, 15780 Zografou, Greece
| | - K S Suh
- Korea Atomic Energy Research Institute, Daedeok-Daero 989-111, Yuseong-Gu, Daejeon, Republic of Korea
| | - G de With
- Nuclear Research and Consultancy Group, Utrechtseweg 310, 6800 ES Arnhem, Netherlands
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Lee E, Kim DH, Kim HW, Denlinger JD, Kim H, Kim J, Kim K, Min BI, Min BH, Kwon YS, Kang JS. The 7 × 1 Fermi Surface Reconstruction in a Two-dimensional f -electron Charge Density Wave System: PrTe3. Sci Rep 2016; 6:30318. [PMID: 27453329 PMCID: PMC4958976 DOI: 10.1038/srep30318] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [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: 02/11/2016] [Accepted: 07/04/2016] [Indexed: 11/29/2022] Open
Abstract
The electronic structure of a charge density wave (CDW) system PrTe3 and its modulated structure in the CDW phase have been investigated by employing ARPES, XAS, Pr 4 f RPES, and first-principles band structure calculation. Pr ions are found to be nearly trivalent, supporting the CDW instability in the metallic Te sheets through partial filling. Finite Pr 4 f spectral weight is observed near the Fermi level, suggesting the non-negligible Pr 4 f contribution to the CDW formation through the Pr 4 f -Te 5p hybridization. The two-fold symmetric features in the measured Fermi surface (FS) of PrTe3 are explained by the calculated FS for the assumed 7 × 1 CDW supercell formation in Te sheets. The shadow bands and the corresponding very weak FSs are observed, which originate from both the band folding due to the 3D interaction of Te sheets with neighboring Pr-Te layers and that due to the CDW-induced FS reconstruction. The straight vertical FSs are observed along kz, demonstrating the nearly 2D character for the near-EF states. The observed linear dichroism reveals the in-plane orbital character of the near-EF Te 5p states.
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Affiliation(s)
- Eunsook Lee
- Department of Physics, The Catholic University of Korea, Bucheon 14662, Korea
| | - D H Kim
- Department of Physics, The Catholic University of Korea, Bucheon 14662, Korea
| | - Hyun Woo Kim
- Department of Physics, The Catholic University of Korea, Bucheon 14662, Korea
| | - J D Denlinger
- Advanced Light Source (ALS), Lawrence Berkeley Laboratory, Berkeley, CA 12345, USA
| | - Heejung Kim
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Korea
| | - Junwon Kim
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Korea
| | - Kyoo Kim
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Korea.,MPPC CPM, Pohang University of Science and Technology, Pohang 37673, Korea
| | - B I Min
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Korea
| | - B H Min
- Department of Emerging Materials Science, DGIST, Daegu 42988, Korea
| | - Y S Kwon
- Department of Emerging Materials Science, DGIST, Daegu 42988, Korea
| | - J-S Kang
- Department of Physics, The Catholic University of Korea, Bucheon 14662, Korea
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Kim B, Kim BH, Kim K, Min BI. Substrate-tuning of correlated spin-orbit oxides revealed by optical conductivity calculations. Sci Rep 2016; 6:27095. [PMID: 27256281 PMCID: PMC4891771 DOI: 10.1038/srep27095] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [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: 12/15/2015] [Accepted: 05/11/2016] [Indexed: 11/10/2022] Open
Abstract
We have systematically investigated substrate-strain effects on the electronic structures of two representative Sr-iridates, a correlated-insulator Sr2IrO4 and a metal SrIrO3. Optical conductivities obtained by the ab initio electronic structure calculations reveal that the tensile strain shifts the optical peak positions to higher energy side with altered intensities, suggesting the enhancement of the electronic correlation and spin-orbit coupling (SOC) strength in Sr-iridates. The response of the electronic structure upon tensile strain is found to be highly correlated with the direction of magnetic moment, the octahedral connectivity, and the SOC strength, which cooperatively determine the robustness of Jeff = 1/2 ground states. Optical responses are analyzed also with microscopic model calculation and compared with corresponding experiments. In the case of SrIrO3, the evolution of the electronic structure near the Fermi level shows high tunability of hole bands, as suggested by previous experiments.
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Affiliation(s)
- Bongjae Kim
- Department of Physics, PCTP, Pohang University of Science and Technology, Pohang, 37673, Korea
| | - Beom Hyun Kim
- Department of Physics, PCTP, Pohang University of Science and Technology, Pohang, 37673, Korea
| | - Kyoo Kim
- Department of Physics, PCTP, Pohang University of Science and Technology, Pohang, 37673, Korea
- MPPC CPM, Pohang University of Science and Technology, Pohang, 37673, Korea
| | - B. I. Min
- Department of Physics, PCTP, Pohang University of Science and Technology, Pohang, 37673, Korea
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10
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Kang CJ, Denlinger JD, Allen JW, Min CH, Reinert F, Kang BY, Cho BK, Kang JS, Shim JH, Min BI. Electronic Structure of YbB_{6}: Is it a Topological Insulator or Not? Phys Rev Lett 2016; 116:116401. [PMID: 27035312 DOI: 10.1103/physrevlett.116.116401] [Citation(s) in RCA: 5] [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] [Received: 08/22/2015] [Indexed: 06/05/2023]
Abstract
To finally resolve the controversial issue of whether or not the electronic structure of YbB_{6} is nontrivially topological, we have made a combined study using angle-resolved photoemission spectroscopy (ARPES) of the nonpolar (110) surface and density functional theory (DFT). The flat-band conditions of the (110) ARPES avoid the strong band bending effects of the polar (001) surface and definitively show that YbB_{6} has a topologically trivial B 2p-Yb 5d semiconductor band gap of ∼0.3 eV. Accurate determination of the low energy band topology in DFT requires the use of a modified Becke-Johnson exchange potential incorporating spin-orbit coupling and an on-site Yb 4f Coulomb interaction U as large as 7 eV. The DFT result, confirmed by a more precise GW band calculation, is similar to that of a small gap non-Kondo nontopological semiconductor. Additionally, the pressure-dependent electronic structure of YbB_{6} is investigated theoretically and found to transform into a p-d overlap semimetal with small Yb mixed valency.
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Affiliation(s)
- Chang-Jong Kang
- Department of Physics, PCTP, Pohang University of Science and Technology, (POSTECH) Pohang 37673, Korea
| | - J D Denlinger
- Advanced Light Source, Lawrence Berkeley Laboratory, Berkeley, California 94720, USA
| | - J W Allen
- Department of Physics, Randall Laboratory, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Chul-Hee Min
- Universität Würzburg, Experimentelle Physik VII, 97074 Würzburg, Germany
| | - F Reinert
- Universität Würzburg, Experimentelle Physik VII, 97074 Würzburg, Germany
| | - B Y Kang
- School of Materials Science and Engineering, GIST, Gwangju 61005, Korea
| | - B K Cho
- School of Materials Science and Engineering, GIST, Gwangju 61005, Korea
| | - J-S Kang
- Department of Physics, The Catholic University of Korea, Bucheon 14662, Korea
| | - J H Shim
- Department of Physics, PCTP, Pohang University of Science and Technology, (POSTECH) Pohang 37673, Korea
- Department of Chemistry and Division of Advanced Nuclear Engineering, POSTECH, Pohang 37673, Korea
| | - B I Min
- Department of Physics, PCTP, Pohang University of Science and Technology, (POSTECH) Pohang 37673, Korea
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Kim S, Kim K, Min BI. The mechanism of charge density wave in Pt-based layered superconductors: SrPt2As2 and LaPt2Si2. Sci Rep 2015; 5:15052. [PMID: 26449877 PMCID: PMC4598799 DOI: 10.1038/srep15052] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [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: 06/24/2015] [Accepted: 09/10/2015] [Indexed: 11/09/2022] Open
Abstract
The intriguing coexistence of the charge density wave (CDW) and superconductivity in SrPt2As2 and LaPt2Si2 has been investigated based on the ab initio density functional theory band structure and phonon calculations. We have found that the CDW instabilities for both cases arise from the q-dependent electron-phonon coupling with quasi-nesting feature of the Fermi surface. The band structure obtained by the band-unfolding technique reveals the sizable q-dependent electron-phonon coupling responsible for the CDW instability. The local split distortions of Pt atoms in the [As-Pt-As] layers play an essential role in driving the five-fold supercell CDW instability as well as the phonon softening instability in SrPt2As2. By contrast, the CDW and phonon softening instabilities in LaPt2Si2 occur without split distortions of Pt atoms. The phonon calculations suggest that the CDW and the superconductivity coexist in [X-Pt-X] layers (X = As or Si) for both cases.
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Affiliation(s)
- Sooran Kim
- Department of Physics, Pohang University of Science and Technology, Pohang, 790-784, Korea
| | - Kyoo Kim
- Department of Physics, Pohang University of Science and Technology, Pohang, 790-784, Korea.,c_CCMR, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - B I Min
- Department of Physics, Pohang University of Science and Technology, Pohang, 790-784, Korea
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Kang CJ, Choi HC, Kim K, Min BI. Topological Properties and the Dynamical Crossover from Mixed-Valence to Kondo-Lattice Behavior in the Golden Phase of SmS. Phys Rev Lett 2015; 114:166404. [PMID: 25955062 DOI: 10.1103/physrevlett.114.166404] [Citation(s) in RCA: 4] [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: 12/09/2014] [Indexed: 06/04/2023]
Abstract
We have investigated temperature-dependent behaviors of electronic structure and resistivity in a mixed-valent golden phase of SmS, based on the dynamical mean-field-theory band-structure calculations. Upon cooling, the coherent Sm 4f bands are formed to produce the hybridization-induced pseudogap near the Fermi level, and accordingly the topology of the Fermi surface is changed to exhibit a Lifshitz-like transition. The surface states emerging in the bulk gap region are found to be not topologically protected states but just typical Rashba spin-polarized states, indicating that SmS is not a topological Kondo semimetal. From the analysis of anomalous resistivity behavior in SmS, we have identified universal energy scales, which characterize the Kondo-mixed-valent semimetallic systems.
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Affiliation(s)
- Chang-Jong Kang
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Hong Chul Choi
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Kyoo Kim
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
- c_CCMR, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - B I Min
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
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13
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Kim K, Kim S, Ko KT, Lee H, Park JH, Yang JJ, Cheong SW, Min BI. Origin of first-order-type electronic and structural transitions in IrTe2. Phys Rev Lett 2015; 114:136401. [PMID: 25884128 DOI: 10.1103/physrevlett.114.136401] [Citation(s) in RCA: 6] [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] [Received: 08/07/2014] [Indexed: 06/04/2023]
Abstract
We have explored the origin of unusual first-order-type electronic and structural transitions in IrTe2, based on the first-principles total energy density functional theory analysis. We have clarified that the structural transition occurs through the interplay among the charge density wavelike lattice modulation with q1/5=(1/5,0,1/5), in-plane dimer ordering, and the uniform lattice deformation. The Ir-Ir dimer formation via a molecular-orbital version of the Jahn-Teller distortion in the Ir-Ir zigzag stripe is found to play the most important role in producing the charge disproportionation state. Angle-resolved photoemission spectroscopy reveals the characteristic features of structural transition, which are in good agreement with the density functional theory bands obtained by the band-unfolding technique.
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Affiliation(s)
- Kyoo Kim
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
- c_CCMR, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Sooran Kim
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - K-T Ko
- c_CCMR, Pohang University of Science and Technology, Pohang 790-784, Korea
- MPPC_CPM, Pohang University of Science and Technology, Pohang 790-784, Korea
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, Dresden D-01187, Germany
| | - Hwangho Lee
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
- c_CCMR, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - J-H Park
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
- c_CCMR, Pohang University of Science and Technology, Pohang 790-784, Korea
- MPPC_CPM, Pohang University of Science and Technology, Pohang 790-784, Korea
- Division of Advanced Materials Science, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - J J Yang
- c_CCMR, Pohang University of Science and Technology, Pohang 790-784, Korea
- Laboratory for Pohang Emergent Materials. Pohang University of Science and Technology, Pohang 790-784, Korea
| | - S-W Cheong
- Laboratory for Pohang Emergent Materials. Pohang University of Science and Technology, Pohang 790-784, Korea
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Piscataway, New Jersey 08854, USA
| | - B I Min
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
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14
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Eom MJ, Kim K, Jo YJ, Yang JJ, Choi ES, Min BI, Park JH, Cheong SW, Kim JS. Dimerization-induced Fermi-surface reconstruction in IrTe2. Phys Rev Lett 2014; 113:266406. [PMID: 25615364 DOI: 10.1103/physrevlett.113.266406] [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: 07/28/2014] [Indexed: 06/04/2023]
Abstract
We report a de Haas-van Alphen (dHvA) oscillation study on IrTe2 single crystals showing complex dimer formations. By comparing the angle dependence of dHvA oscillations with band structure calculations, we show distinct Fermi surface reconstruction induced by a 1/5-type and a 1/8-type dimerizations. This verifies that an intriguing quasi-two-dimensional conducting plane across the layers is induced by dimerization in both cases. A phase transition to the 1/8 phase with higher dimer density reveals that local instabilities associated with intra- and interdimer couplings are the main driving force for complex dimer formations in IrTe2.
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Affiliation(s)
- Man Jin Eom
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Kyoo Kim
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Y J Jo
- Department of Physics, Kyungpook National University, Daegu 702-701, Korea
| | - J J Yang
- Laboratory for Pohang Emergent Materials, Pohang University of Science and Technology, Pohang 790-784, Korea and Max Plank POSTECH Center for Complex Phase Materials, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - E S Choi
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
| | - B I Min
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - J-H Park
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea and Max Plank POSTECH Center for Complex Phase Materials, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - S-W Cheong
- Laboratory for Pohang Emergent Materials, Pohang University of Science and Technology, Pohang 790-784, Korea and Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Piscataway, New Jersey 08854, USA
| | - Jun Sung Kim
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
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15
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Noh HJ, Jeong J, Chang B, Jeong D, Moon HS, Cho EJ, Ok JM, Kim JS, Kim K, Min BI, Lee HK, Kim JY, Park BG, Kim HD, Lee S. Direct observation of localized spin antiferromagnetic transition in PdCrO2 by angle-resolved photoemission spectroscopy. Sci Rep 2014; 4:3680. [PMID: 24419488 PMCID: PMC3890906 DOI: 10.1038/srep03680] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [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: 08/29/2013] [Accepted: 12/17/2013] [Indexed: 11/09/2022] Open
Abstract
We report the first case of the successful measurements of a localized spin antiferromagnetic transition in delafossite-type PdCrO2 by angle-resolved photoemission spectroscopy (ARPES). This demonstrates how to circumvent the shortcomings of ARPES for investigation of magnetism involved with localized spins in limited size of two-dimensional crystals or multi-layer thin films that neutron scattering can hardly study due to lack of bulk compared to surface. Also, our observations give direct evidence for the spin ordering pattern of Cr(3+) ions in PdCrO2 suggested by neutron diffraction and quantum oscillation measurements, and provide a strong constraint that has to be satisfied by a microscopic mechanism for the unconventional anomalous Hall effect recently reported in this system.
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Affiliation(s)
- Han-Jin Noh
- Department of Physics, Chonnam National University, Gwangju 500-757, Korea
| | - Jinwon Jeong
- Department of Physics, Chonnam National University, Gwangju 500-757, Korea
| | - Bin Chang
- Department of Physics, Chonnam National University, Gwangju 500-757, Korea
| | - Dahee Jeong
- Department of Physics, Chonnam National University, Gwangju 500-757, Korea
| | - Hyun Sook Moon
- Department of Physics, Chonnam National University, Gwangju 500-757, Korea
| | - En-Jin Cho
- Department of Physics, Chonnam National University, Gwangju 500-757, Korea
| | - Jong Mok Ok
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Jun Sung Kim
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Kyoo Kim
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - B I Min
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Han-Koo Lee
- Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Jae-Young Kim
- Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Byeong-Gyu Park
- Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Hyeong-Do Kim
- 1] Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang 790-784, Korea [2]
| | - Seongsu Lee
- Korea Atomic Energy Research Institute, Daejeon, 305-353, Korea
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16
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Ok JM, Jo YJ, Kim K, Shishidou T, Choi ES, Noh HJ, Oguchi T, Min BI, Kim JS. Quantum oscillations of the metallic triangular-lattice antiferromagnet PdCrO2. Phys Rev Lett 2013; 111:176405. [PMID: 24206508 DOI: 10.1103/physrevlett.111.176405] [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: 02/16/2013] [Revised: 07/15/2013] [Indexed: 06/02/2023]
Abstract
We report the electronic and transport properties of the triangular antiferromagnet PdCrO(2) at high magnetic fields up to 33 T, using measurements of the de Haas-van Alphen oscillations and the Hall resistivity. The de Haas-van Alphen oscillations below the magnetic ordering temperature T(N) reveal several two-dimensional Fermi surfaces of smaller size than those found in nonmagnetic PdCoO(2), consistent with the band structure calculations. This evidences Fermi surface reconstruction due to the 120° helical ordering of the localized Cr spins, suggesting significant coupling of the itinerant electrons to the underlying spin texture. This induces the nonlinear Hall resistivity at low temperatures via the magnetic breakdown in the reconstructed Fermi surface. Furthermore, such a coupling leads to the unconventional anomalous Hall effects near T(N) due to the field-induced spin chirality at high magnetic fields.
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Affiliation(s)
- Jong Mok Ok
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
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17
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Kim BH, Khaliullin G, Min BI. Magnetic couplings, optical spectra, and spin-orbit exciton in 5d electron Mott insulator Sr2IrO4. Phys Rev Lett 2012; 109:167205. [PMID: 23215122 DOI: 10.1103/physrevlett.109.167205] [Citation(s) in RCA: 7] [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] [Received: 05/11/2012] [Indexed: 06/01/2023]
Abstract
Based on the microscopic model including spin-orbit coupling, on-site Coulomb and Hund's interactions, as well as crystal field effects, we investigate the magnetic and optical properties of Sr(2)IrO(4). Taking into account all intermediate state multiplets generated by virtual hoppings of electrons, we calculate the isotropic, pseudodipolar, and Dzyaloshinsky-Moriya coupling constants, which describe the experiment quite well. The optical conductivity σ(ω) evaluated by the exact diagonalization method shows two peaks at ~0.5 and ~1.0 eV in agreement with experiment. The two-peak structure of σ(ω) arises from the unusual Fano-type overlap between the electron-hole continuum of the J(eff)=1/2 band and the intrasite spin-orbit exciton observed recently in Sr(2)IrO(4).
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Affiliation(s)
- Beom Hyun Kim
- Department of Physics, PCTP, Pohang University of Science and Technology, Pohang 790-784, Korea
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18
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Yang JJ, Choi YJ, Oh YS, Hogan A, Horibe Y, Kim K, Min BI, Cheong SW. Charge-orbital density wave and superconductivity in the strong spin-orbit coupled IrTe2:Pd. Phys Rev Lett 2012; 108:116402. [PMID: 22540494 DOI: 10.1103/physrevlett.108.116402] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Indexed: 05/31/2023]
Abstract
Using transmission electron microscopy, the anomalies in resistivity and magnetic susceptibility at ~262 K in IrTe2 are found to accompany the superlattice peaks with q[over q=(1/5,0,-1/5). The wave vector is consistent with our theoretical calculation for the Fermi surface nesting vector, indicating that the ~262 K transition is of the charge-orbital density wave (DW) type. We also discovered that both Pd intercalation and substitution induce bulk superconductivity with T(c) up to ~3 K, which competes with DW in a quantum critical pointlike manner.
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Affiliation(s)
- J J Yang
- Laboratory for Pohang Emergent Materials, Pohang University of Science and Technology, Pohang, Korea
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19
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Choi HC, Min BI, Shim JH, Haule K, Kotliar G. Temperature-dependent Fermi surface evolution in heavy fermion CeIrIn5. Phys Rev Lett 2012; 108:016402. [PMID: 22304274 DOI: 10.1103/physrevlett.108.016402] [Citation(s) in RCA: 7] [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] [Received: 06/07/2011] [Indexed: 05/31/2023]
Abstract
We address theoretically the evolution of the heavy fermion Fermi surface (FS) as a function of temperature (T), using a first principles dynamical mean-field theory approach combined with density functional theory. We focus on the archetypical heavy electrons in CeIrIn{5}. Upon cooling, both the quantum oscillation frequencies and cyclotron masses show logarithmic scaling behavior [∼ln(T{0}/T)] with different characteristic temperatures T{0}=130 and 50 K, respectively. The enlargement of the electron FSs at low T is accompanied by topological changes around T=10-50 K. The resistivity coherence peak observed at T≃50 K is the result of the competition between the binding of incoherent 4f electrons to the spd conduction electrons at Fermi level (E{F}) and the formation of coherent 4f electrons.
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Affiliation(s)
- Hong Chul Choi
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
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20
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Ko KT, Kim K, Kim SB, Kim HD, Kim JY, Min BI, Park JH, Chang FH, Lin HJ, Tanaka A, Cheong SW. RKKY ferromagnetism with Ising-like spin states in intercalated Fe(1/4)TaS2. Phys Rev Lett 2011; 107:247201. [PMID: 22243021 DOI: 10.1103/physrevlett.107.247201] [Citation(s) in RCA: 6] [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: 03/02/2011] [Indexed: 05/31/2023]
Abstract
We investigated the magnetic nature of Fe(1/4)TaS2 using x-ray absorption spectroscopy, photoemission spectroscopy, and first principles band calculations. The results show a large unquenched orbital magnetic moment (∼1.0 μ(B)/Fe) at intercalated Fe sites, resulting in a gigantic magnetic anisotropy (H(A)≃60 T). The magnetic coupling is well understood in terms of the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction, suggesting a novel RKKY ferromagnet with Ising-type spin states. We also found that this indirect exchange coupling between the neighboring Fe spins is ferromagnetic and maximized at the Fe-Fe distance of 2×2 superstructure.
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Affiliation(s)
- K-T Ko
- c_CCMR & Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
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21
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Noh HJ, Jeong J, Jeong J, Cho EJ, Kim SB, Kim K, Min BI, Kim HD. Anisotropic electric conductivity of delafossite PdCoO2 studied by angle-resolved photoemission spectroscopy. Phys Rev Lett 2009; 102:256404. [PMID: 19659104 DOI: 10.1103/physrevlett.102.256404] [Citation(s) in RCA: 11] [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] [Received: 03/11/2009] [Indexed: 05/28/2023]
Abstract
An explicit connection between the electronic structure and the anisotropic high conductivity of delafossite-type PdCoO2 has been established by angle-resolved photoemission spectroscopy (ARPES) and core-level x-ray photoemission spectroscopy. The ARPES spectra show that a large hexagonal electronlike Fermi surface (FS) consists of very dispersive Pd 4d states. The carrier velocity and lifetime are determined from the ARPES data, and the conductivity is calculated by a solution of the Boltzmann equation, which demonstrates that the high anisotropic conductivity originates from the high carrier velocity, the large two-dimensional FS, and the long lifetime of the carriers.
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Affiliation(s)
- Han-Jin Noh
- Department of Physics, Chonnam National University, Gwangju 500-757, Korea.
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22
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Kim K, Choi HC, Min BI. Comment on "Why is polonium simple cubic and so highly anisotropic?". Phys Rev Lett 2009; 102:079701-079702. [PMID: 19257720 DOI: 10.1103/physrevlett.102.079701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2008] [Indexed: 05/27/2023]
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23
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Kang JS, Kim G, Wi SC, Lee SS, Choi S, Cho S, Han SW, Kim KH, Song HJ, Shin HJ, Sekiyama A, Kasai S, Suga S, Min BI. Spatial chemical inhomogeneity and local electronic structure of Mn-doped Ge ferromagnetic semiconductors. Phys Rev Lett 2005; 94:147202. [PMID: 15904100 DOI: 10.1103/physrevlett.94.147202] [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: 09/02/2004] [Indexed: 05/02/2023]
Abstract
We have investigated the chemical distributions and the local electronic structure of potential diluted magnetic semiconductor Ge0.94Mn0.06 single crystals using scanning photoelectron microscopy (SPEM), x-ray absorption spectroscopy (XAS), and photoemission spectroscopy (PES). The SPEM image shows the stripe-shaped microstructures, which arise from the chemical phase separation between the Mn-rich and Mn-depleted phases. The Mn 2p XAS shows that the Mn ions in the Mn-rich region are in the divalent high-spin Mn2+ states but that they do not form metallic Mn clusters. The Mn 3d PES spectrum exhibits a peak centered at approximately 4 eV below E(F) and the negligible spectral weight near E(F). This study suggests that the observed ferromagnetism in Ge1-xMnx arises from the phase-separated Mn-rich phase.
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Affiliation(s)
- J-S Kang
- Department of Physics, The Catholic University of Korea, Puchon 420-743, Korea
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24
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Yu U, Min BI. Magnetic and transport properties of the magnetic Polaron: application to Eu1-xLaxB6 system. Phys Rev Lett 2005; 94:117202. [PMID: 15903884 DOI: 10.1103/physrevlett.94.117202] [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: 09/08/2004] [Indexed: 05/02/2023]
Abstract
To understand the role of the magnetic polaron in magnetic and transport properties of Eu(1-x)LaxB6, we investigate the low carrier density ferromagnetic Kondo lattice model by using the Monte Carlo methods. We demonstrate that the magnetic-polaronic (MP) state with the insulating nature is realized in the phase-separated region in between the ferromagnetic and antiferromagnetic (AFM) states in the phase diagram. The insulating behaviors of EuB6 just above T(C) and of Eu(1-x)LaxB6 with 0.05<x<0.2 are well explained by MP states in the paramagnetic and the AFM background, respectively. The Eu vacancy plays a crucial role in forming the bound magnetic polaron and so producing the resistivity peak in EuB6. By applying the weak magnetic field, the AFM metallic ground state is destroyed into the MP state, but the metallic behavior is restored by the strong magnetic field, as is observed for Eu(1-x)LaxB6 with 0.2< x < 0.3.
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Affiliation(s)
- Unjong Yu
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
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25
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Shim JH, Kang JS, Min BI. Electronic structures of RTe2 (R = La,Ce): a clue to the pressure-induced superconductivity in CeTe1.82. Phys Rev Lett 2004; 93:156406. [PMID: 15524914 DOI: 10.1103/physrevlett.93.156406] [Citation(s) in RCA: 4] [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] [Received: 04/28/2004] [Indexed: 05/24/2023]
Abstract
Electronic structures of RTe2 (R=La,Ce) have been investigated by using the local spin density approximation (LSDA) and the LSDA + U (U: on-site Coulomb interaction) band methods. Both LaTe2 and CeTe2 show the very similar Fermi surface nesting features along the [100] direction, which drive the charge-density wave (CDW) instability in the Te(1) sheets. The contribution near E(F) from Ce 4f states is negligible in agreement with the measured ARPES spectra. In the semimetallic CDW-distorted RTe2, both Te vacancy and pressure induce the charge transfer from Te(1) 5p to R 5d states, producing the enhanced density of states at E(F). We suggest that these increased self-doped Te(1) 5p hole carriers are responsible for the pressure-induced superconductivity in nonstoichiometric CeTe1.82.
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Affiliation(s)
- J H Shim
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
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26
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Skrypnyk YV, Min BI. On the Relation between the Presence of the Resonance and the Type of the Spectrum Rearrangement in a Disordered System. ACTA ACUST UNITED AC 2002. [DOI: 10.1143/ptp.108.1021] [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: 11/05/2022]
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27
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Choi GS, Oha SD, Han JB, Bae HS, Cho YW, Yun YS, Lee WK, Ahn HJ, Min BI. Modulation of natural killer cell activity affected by electroacupuncture through lateral hypothalamic area in rats. Neurosci Lett 2002; 329:1-4. [PMID: 12161248 DOI: 10.1016/s0304-3940(02)00551-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Electroacupuncture (EA) has been reported to modulate natural killer cell (NK cell) activities. Also it is well known that hypothalamus directly mediates the effects of EA on analgesia. Especially lateral hypothalamic area (LHA) is related to splenic NK cell activities. In order to investigate the relationship between hypothalamus and effects of EA on NK cell activity, lesions have been made bilaterally at LHA of Spraque-Dawley rats. Subsequently, NK cell cytotoxities of normal and lesioned rats were measured with (51)Cr release immunoassay after EA stimulation for 2 and 14 days. NK cell activity of EA group was significantly higher than sham group. In addition, lesions abolished effects of EA on NK cell activity. These results strongly suggest that LHA is closely related to increase of NK cell activity induced by EA.
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Affiliation(s)
- G S Choi
- Department of East-West Medicine, Graduate School, Kyung Hee University, Seoul, South Korea
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28
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Jeong HJ, Lee JJ, Hahm ET, Han SH, Min BI, Cho YW. Role of protein kinase C in opioid modulation of glycine-gated Cl(-) current in rat periaqueductal gray neuron. Eur J Pharmacol 2001; 431:143-50. [PMID: 11728420 DOI: 10.1016/s0014-2999(01)01397-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The Role of protein kinase C in the modulatory effect of a mu-opioid receptor agonist, [D-Ala(2),N-Me-Phe(4),Gly(5)-ol]enkephalin (DAMGO), on the glycine-gated Cl(-) current was examined in acutely dissociated rat periaqueductal gray neurons. Using the nystatin-perforated patch-clamp technique, the neurons were voltage-clamped at -60 mV. The glycine-gated Cl(-) current (I(Gly)) was sensitive to strychnine. On pretreatment with 1 microM DAMGO, the 30-microM glycine response increased with time and showed a maximum amplitude of 209+/-37% of control. After a protein kinase C activator, phorbol-12-myristate-13-acetate (PMA, 0.1 microM) as pretreatment, I(Gly) increased to 138+/-6% of control. The DAMGO potentiation of I(Gly) was not altered by coapplication with PMA. Although protein kinase C inhibitors, chelerythrine (3 microM) and 2-[1-(3-dimethylaminopropyl)indol-3-yl]-3-(indol-3-yl) maleimide (GF109203X, 1 microM), did not alter I(Gly), the DAMGO-induced potentiation of I(Gly) was reduced to 161+/-21% or 164+/-31% of the control after coapplication with chelerythrine or GF109203X, respectively. These results indicate that the potentiation of I(Gly) by a mu-opioid receptor agonist is partly mediated by activation of protein kinase C.
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Affiliation(s)
- H J Jeong
- Department of Physiology, College of Medicine, Kyung Hee University, Seoul 130-701, South Korea
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Cho YW, Han SH, Min BI, Rhee JS, Akaike N. Antagonizing effect of protein kinase C activation on the mu-opioid agonist-induced inhibition of high voltage-activated calcium current in rat periaqueductal gray neuron. Brain Res 2001; 916:61-9. [PMID: 11597591 DOI: 10.1016/s0006-8993(01)02864-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Opioids have been thought to induce analgesia by activating the descending pain control system, especially at the level of periaqueductal gray, and regulate the neurotransmitter release through the inhibition of calcium channel. In the present study, the modulatory effects of protein kinase C and protein kinase A on the mu-opioid agonist-induced inhibition of the high-voltage activated calcium current were examined in the acutely dissociated rat periaqueductal gray neurons with the nystatin-perforated patch-clamp technique. Among 505 neurons tested, the barium current passing through the high-voltage activated calcium channels of 172 neurons (34%) were inhibited by 32+/-3% with the application of an mu-opioid agonist, [D-Ala(2),N-MePhe(4),Gly(5)-ol]-enkephalin (DAMGO, 1 microM). The barium currents itself and the DAMGO-induced inhibitory effects were not affected by the application of either an adenylate cyclase activator (forskolin, 1 microM) or a protein kinase inhibitor (staurosporin, 10 nM) for 2 min. The DAMGO inhibition was completely and irreversibly antagonized by the application of a protein kinase C activator, phorbol-12-myristate-13-acetate (PMA, 1 microM) for 2 min without any alteration of the barium current itself. However, the antagonizing effect of PMA was completely abolished by the application of 10 nM staurosporin for 2 min. After then, PMA did not show the antagonizing effect any more. Inversely, when staurosporin was applied before PMA, the antagonizing effect of PMA was also not shown. These results demonstrate that the mu-opioid agonist-induced inhibition of the periaqueductal gray neuronal high-voltage activated calcium current can be antagonized by protein kinase C activation. This finding may provide us a significant clue to understand the action mechanism of opioid-induced analgesia in the periaqueductal gray.
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Affiliation(s)
- Y W Cho
- Department of Physiology, College of Medicine, Kyung Hee University, Seoul 130-701, South Korea.
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Jeong HJ, Han SH, Min BI, Cho YW. 5-HT1A receptor-mediated activation of G-protein-gated inwardly rectifying K+ current in rat periaqueductal gray neurons. Neuropharmacology 2001; 41:175-85. [PMID: 11489454 DOI: 10.1016/s0028-3908(01)00062-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
5-hydroxytryptamine (5-HT) has been reported to modulate analgesia produced by opioids or electrical stimulation of the periaqueductal gray (PAG). 5-HT increases K+ conductance and inhibits the firing activity of the PAG neurons. We examined the electrophysiological and pharmacological characteristics of the K+ current involved in 5-HT-induced hyperpolarization of dissociated rat PAG neurons. Among the neurons tested, 5-HT activated inward K+ currents in 30-40%, whilst the remaining 60-70% did not respond to 5-HT. 5-HT activated an inwardly rectifying K+ current (I5-HT) in a concentration- and voltage-dependent manner. I5-HT was mimicked by a 5-HT1A receptor selective agonist, 8-OH-DPAT, and was reversibly blocked by a 5-HT1A receptor antagonist, piperazine maleate, but not by a 5-HT2 receptor antagonist, ketanserin. I5-HT was sensitive to K+ channel blockers such as quinine and Ba2+, but insensitive to 4-aminopyridine, Cs+ and tetraethylammonium. I5-HT was inhibited by GDP(beta)s and was irreversibly activated by GTP(gamma)s. I5-HT was significantly suppressed by N-ethylmaleimide and pertussis toxin, but not by cholera toxin. Second messenger modulators such as staurosporin, forskolin, and phorbol-12-myristate-13-acetate did not alter I5-HT. The present study indicates that 5-HT-induced hyperpolarization of the PAG neurons results from activation of the pertussis toxin-sensitive G-protein-coupled inwardly rectifying K+ currents through 5-HT1A receptors.
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Affiliation(s)
- H J Jeong
- Department of Physiology, College of Medicine, Kyung Hee University, Seoul 130-701, South Korea
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Abstract
BACKGROUND This study was designed to evaluate the effects of electroacupuncture on sphincter of Oddi (SO) motility in humans and to associate the manometric findings with cholecystokinin (CCK) plasma levels. METHODS Eleven patients (M:F = 5:6) with various kinds of biliary disorders were enrolled. SO motility was monitored with conventional low-compliance, continuous perfusion technique at ERCP (n = 9) or via percutaneous transhepatic cholangioscopy (n = 2). After baseline monitoring for phasic wave contractions of SO, electroacupuncture was applied at a specific acupoint GB 34. A nonspecific acupoint 5 cm away from GB 34 was selected as a control. Manometric parameters of the SO were also measured in 6 subjects during stimulation of the control acupoint. CCK plasma levels were measured during electroacupuncture stimulation. RESULTS All manometric parameters including basal pressure, amplitude, frequency, and duration of phasic wave contractions of the SO were significantly decreased (p < 0.05) during electroacupuncture stimulation. The inhibition of SO contractility was accompanied by increased CCK plasma levels. After discontinuation of electroacupuncture stimulation, restoration of amplitude and duration to basal conditions was noted. A tendency toward return of SO basal pressure and contractile frequency to baseline was also observed. Stimulation of the control acupoint did not affect SO contractility. CONCLUSION Electroacupuncture stimulation of acupoint GB 34 resulted in reversible inhibition of SO contraction in humans. The response of SO to electroacupuncture stimulation may be mediated by some neurohormonal mechanisms including CCK release.
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Affiliation(s)
- S K Lee
- Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
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32
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Abstract
The method of quick insertion and withdrawal of the needle (QIW) in acupuncture is a technique of stimulation not retaining the needle in the acupuncture point. We examined the analgesic effects of five different types of QIW along with the changes of stimulation quantity, time, and depth, and then compared the analgesic effect of the most effective QIW to that of plain acupuncture (PA). When tail-flick latency values between the strongest QIW-I group and PA group were compared, there was no significant difference (analyzed by t-test). These results indicate that QIW technique has an analgesic effect similar to PA technique and that the conditions, which for the QIW-I was shown the most effective analgesia, are a duration of 5 s at intervals of 1 s and at the depth of 3 mm.
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Affiliation(s)
- E S Uom
- Department of East-West Medicine, Graduate School, Kyung Hee University, Seoul, South Korea
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33
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Abstract
To investigate the temporal progression of atherogenesis on the aorta and involvement of the monocyte-macrophage system in the liver and spleen, we fed 74 rabbits with high fat (14 or 7 gm%) and cholesterol (2 and 1%) diets for 4 to over 24 weeks. Using both light and electron microscopies, we found that the fibro-fatty areas on the luminal surface of aortas was spread over along the feeding time dependently. The fat deposits also in the liver and spleen worsened depending on the time of feeding the atherogenic diets. Not only monocyte-derived foam cells, but also parenchymatous cells in the liver and spleen involved become fat-laden cells. According to these results, we propose that there are three stages: 1) the primary seeding, 2) the intermediate maturing and 3) the advanced periods. These periods may play very important roles in designing the management and treatment of atherosclerotic patients.
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Affiliation(s)
- S H Song
- Department of Physiology, College of Medicine, Kyung Hee University, Seoul, Korea
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34
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Abstract
We have explored the origin of the observed giant magnetic moments ( approximately 7&mgr;(B)) of Fe impurities on the surface and in the bulk of Cs films, using the relativistic local-spin-density-approximation method. We have found that Fe impurities in Cs behave differently from those in noble metals or in Pd. Whereas the induced spin polarization of Cs atoms is negligible, the Fe ion itself is a source of the giant magnetic moment. The 3d electrons of Fe in Cs are localized as the 4f electrons in rare-earth ions so that the orbital magnetic moment becomes as large as the spin magnetic moment. The calculated total magnetic moment M = 6.43&mgr;(B) is close to the experimentally observed value.
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Affiliation(s)
- SK Kwon
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
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Kim JH, Min BI, Schmidt D, Lee HJ, Park DS. The difference between electroacupuncture only and electroacupuncture with manipulation on analgesia in rats. Neurosci Lett 2000; 279:149-52. [PMID: 10688051 DOI: 10.1016/s0304-3940(99)00994-5] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Plain acupuncture uses manipulation (rotation or varying the depth of insertion of the needle) to increase its effect. However, in commonly used electroacupunture (EA), variable manipulations have not been used. This study was performed to investigate the possibility of an increase in analgesic effect by adding manipulation to EA. The pain index used was the Tail-Flick latency (TFL) of the rat, which was lightly anesthetized with thiopental sodium (intraperitoneally). Four types of manipulation were used. Rotation and varying the depth of the needle (RN and VN) was employed using two different types of manipulation during each 20 min stimulation of EA. Each manipulation persisted for 1 min out of every 5 min (long - duration and long - interval: LDLI) or 12 s every 1 min (short - duration and short interval: SDSI). EA produced an increase in TFL; peak value was 49.7+/-12.2% of the pre - EA and occurred immediately after cessation of 20 min of EA stimulation. Performing RN or VN combined with EA also increased TFL more than just EA and a greater peak increase in TFL was observed with a SDSI - RN and SDSI - VN as compared to a LDLI - RN and LDLI - VN (77.5+/-13.8, 79.2+/-19.8 and 67.3+/-14.0%, 65.6+/-23.7% of the pre - EA, respectively). These results indicate that manipulation combined with EA produces a more potent antinociception than when only EA is applied.
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Affiliation(s)
- J H Kim
- Department of East-West Medicine, Graduate School, Kyung Hee University, Seoul, South Korea
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Han SH, Cho YW, Kim CJ, Min BI, Rhee JS, Akaike N. Mu-opioid agonist-induced activation of G-protein-coupled inwardly rectifying potassium current in rat periaqueductal gray neurons. Neuroscience 1999; 90:209-19. [PMID: 10188947 DOI: 10.1016/s0306-4522(98)00409-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The characteristics of the inwardly rectifying K+ current activated by a mu-type opioid agonist, D-Ala2,N-MePhe4,Gly5-ol-enkephalin (DAMGO), were examined in the acutely dissociated rat periaqueductal gray neurons using the nystatin-perforated and the conventional whole-cell recording modes under voltage-clamp conditions. DAMGO activated inward currents in a concentration- and voltage-dependent manner. The DAMGO-induced current was an inwardly rectifying K+ current (I(DAMGO)) which was sensitive to K+ channel blockers, quinine and Ba2+ but insensitive to Cs+ and tetraethylammonium. In the conventional whole-cell clamp mode, guanosine 5'-O-(2-thiodiphosphate) trilithium salt (GDPbetas, 0.4 mM) inhibited the amplitude of I(DAMGO) to 28% of that of the initial current. After the intracellular perfusion with guanosine 5'-O-(3-thiotriphosphate) tetralithium salt (GTPgammas, 0.4 mM) for 1 min, the first application of DAMGO irreversibly activated I(DAMGO). By the extracellular application of N-ethylmaleimide at a concentration of 50 microM for 2 min, I(DAMGO) was completely abolished. When a conventional whole-cell patch was made with a patch-pipette containing 1 microg/ml of pertussis toxin together with 1 mM of beta-nicotinamide adenine dinucleotide, I(DAMGO) gradually declined to about 41% of its initial amplitude. The extracellular application of second messenger modulators including protein kinase inhibitor (staurosporin), protein kinase A activators (forskolin, 3-isobutyl-l-methyl-xanthine and dibutyryladenosine 3'5'-cyclic monophosphate) and protein kinase C activators (phorbol-12-myristate-13-acetate and 1-oleoyl-2-acetyl-sn-glycerol) had no effect on I(DAMGO). These results suggest that (i) DAMGO-activated inwardly rectifying K+ current is mediated by pertussis toxin-sensitive guanine nucleotide binding proteins (G-proteins); (ii) the types of G protein involved in I(DAMGO) are Gi and/or Go; and (iii) the G-proteins exert their roles in I(DAMGO) without any mediation of the second messenger systems.
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Affiliation(s)
- S H Han
- Department of Physiology, Kyunghee University College of Medicine, Seoul, South Korea
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Abstract
The mechanism of electroacupuncture (EA) on the stress responses induced by tooth-pulp stimulation was investigated in anesthetized adult female Sprague-Dawley rats. The Hoku point in the Chinese meridian was used for acupuncture stimulation. Constant rectangular current (1 mA) pulses of 5-ms duration were delivered at 3 Hz through a pair of needles for 15 min. As for stress response indexes, we have monitored changes in arterial blood pressure and the levels of blood catecholamines, corticosterone, and ACTH. Arterial blood pressure was increased by high frequency stimulation (0.1 mA, 0.5 ms, 100 Hz for 15 s) of tooth-pulp in the control condition. After EA, we did not observe the same responses of the arterial blood pressure changes with the same stimuli. The tooth-pulp stimulation increased the concentrations of plasma norepinephrine (NE), epinephrine (E), dopamine (DA), corticosterone, and ACTH significantly from the levels of those before stress. After treatment with EA, the stress-induced increase in NE, DA, corticosterone, and ACTH but not the rise in E, were inhibited. When naloxone, an opioid antagonist, was administered intraperitoneally before EA, the effects of EA on stress responses were reduced. In this study, it can be suggested that EA has not only an analgesic effect but also suppressive effects on the stress responses primarily through the mediation of an endogenous opioid.
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Affiliation(s)
- S H Han
- Department of Physiology, College of Medicine, Kyung Hee University, Seoul, South Korea
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Cho ZH, Chung SC, Jones JP, Park JB, Park HJ, Lee HJ, Wong EK, Min BI. New findings of the correlation between acupoints and corresponding brain cortices using functional MRI. Proc Natl Acad Sci U S A 1998; 95:2670-3. [PMID: 9482945 PMCID: PMC19456 DOI: 10.1073/pnas.95.5.2670] [Citation(s) in RCA: 317] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
A preliminary study of the correlation between acupuncture points (acupoints) for the treatment of eye disorders suggested by ancient Oriental literature and the corresponding brain localization for vision described by Western medicine was performed by using functional MRI (fMRI). The vision-related acupoint (VA1) is located in the lateral aspect of the foot, and when acupuncture stimulation is performed there, activation of occipital lobes is seen by fMRI. Stimulation of the eye by directly using light results in similar activation in the occipital lobes by fMRI. The experiment was conducted by using conventional checkerboard 8-Hz light-flash stimulation of the eye and observation of the time-course data. This was followed by stimulation of the VA1 by using the same time-course paradigm as visual light stimulation. Results obtained with 12 volunteers yielded very clean data and very close correlations between visual and acupuncture stimulation. We have also stimulated nonacupoints 2 to 5 cm away from the vision-related acupoints on the foot as a control, and activation in the occipital lobes was not observed. The results obtained demonstrate the correlation between activation of specific areas of brain cortices and corresponding acupoint stimulation predicted by ancient acupuncture literature.
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Affiliation(s)
- Z H Cho
- Department of Radiological Sciences, Psychiatry, and Human Behavior, University of California, Irvine, CA 92697, USA.
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Min BI, Kim CJ, Rhee JS, Akaike N. Modulation of glycine-induced chloride current in acutely dissociated rat periaqueductal gray neurons by mu-opioid agonist DAGO. Brain Res 1996; 734:72-8. [PMID: 8896810] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Effect of a mu-opioid agonist (D-Ala2,N-MePhe4,Gly5-ol-enkephalin, DAGO), on glycine (Gly)-induced chloride current (IGly) was investigated in the periaqueductal gray (PAG) neurons acutely dissociated 1-2-week-old Wistar rats by the use of nystatin-perforated patch recording configuration under voltage-clamp condition. At a holding potential (VH) of -40 mV, DAGO caused a sustained potentiation of IGly at the low concentrations (10(-6)-10(-5) M) but reduced slightly the Gly response at the high concentration (10(-4) M). The reversal potential of IGly was equal to the Cl- equilibrium potential (ECl) and was not changed in the presence of 10(-6) M DAGO. The 10(-5) M Gly response was inhibited by the simultaneous treatment of forskolin and 3-isobutyl-1-methylxanthine (IBMX). H-89, a protein kinase A (PKA) inhibitor, increased the 10(-5) M Gly response but had little effect on the 10(-4) M Gly response. DAGO increased 10(-5) M Gly response in the presence of forskolin and IBMX but, not more than in the absence of forskolin and IBMX. The 10(-5) M Gly response augumented by DAGO was not affected by adding H-89. The present results suggest that the glycine-induced chloride current is cAMP dependent and is inhibited by PKA, and that the potentiation of the glycine response by DAGO is also cAMP dependent and is due to the inhibition of PKA as that of H-89. We conclude that the potentiation of glycine response by DAGO is mediated by an inhibition of cAMP-dependent PKA in the PAG neurons.
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Affiliation(s)
- B I Min
- Department of Physiology, College of Medicine, Kyung Hee University, Tongdaemoon-Gu, Seoul, South Korea
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Kang K, Min BI. Finite-U impurity Anderson model in the presence of an external magnetic field. Phys Rev B Condens Matter 1996; 54:1645-1651. [PMID: 9986008 DOI: 10.1103/physrevb.54.1645] [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: 11/07/2022]
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Lee JD, Min BI. Effects of the finite band width in a two-dimensional electron gas: The renormalization constant and the effective mass. Phys Rev B Condens Matter 1996; 53:10988-10994. [PMID: 9982671 DOI: 10.1103/physrevb.53.10988] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [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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Kang K, Min BI. Equation-of-motion treatment of the impurity Anderson model with a finite on-site Coulomb repulsion. Phys Rev B Condens Matter 1995; 52:10689-10692. [PMID: 9980145 DOI: 10.1103/physrevb.52.10689] [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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Kang J, Sohn JG, Hong JH, Hwang DW, Jeong JI, Benning PJ, Olson CG, Min BI. Photoemission study of valence electrons in La(Co1-xFex)13 (x=0,0.2). Phys Rev B Condens Matter 1995; 52:4360-4365. [PMID: 9981567 DOI: 10.1103/physrevb.52.4360] [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: 04/12/2023]
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Youn SJ, Min BI. Effects of the spin-orbit interaction in Heusler compounds: Electronic structures and Fermi surfaces of NiMnSb and PtMnSb. Phys Rev B Condens Matter 1995; 51:10436-10442. [PMID: 9977738 DOI: 10.1103/physrevb.51.10436] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [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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45
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Lee JD, Kang K, Min BI. Correlation-enhanced electron-phonon interaction in a strongly correlated electron system. Phys Rev B Condens Matter 1995; 51:3850-3855. [PMID: 9979205 DOI: 10.1103/physrevb.51.3850] [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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Kang J, Hwang DW, Hong JH, Jeong JI, Park HK, Moon JH, Lee YP, Benning P, Olson CG, Youn SJ, Min BI. Enhanced Fe 3d spectral weight near the Fermi level in Fe overlayers on Cr. Phys Rev B Condens Matter 1995; 51:1039-1044. [PMID: 9978254 DOI: 10.1103/physrevb.51.1039] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [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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Lee JI, Zhao TS, Kim IG, Min BI, Youn SJ. Electronic structure of Ni-based superconducting quaternary compounds: YNi2B2X (X=B, C, N, and O). Phys Rev B Condens Matter 1994; 50:4030-4033. [PMID: 9976683 DOI: 10.1103/physrevb.50.4030] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [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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48
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Kang J, Hong JH, Hwang DW, Jeong JI, Choi SD, Yang CJ, Lee YP, Olson CG, Kang K, Min BI. Hybridization and correlation effects in the photoemission spectra of RNi2 (R=Ce, Pr, and Nd). Phys Rev B Condens Matter 1994; 49:16248-16255. [PMID: 10010771 DOI: 10.1103/physrevb.49.16248] [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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50
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Min BI, Kang J, Hong JH, Jeong JI, Lee YP, Choi SD, Lee WY, Yang CJ, Olson CG. Electronic and magnetic structures of the rare-earth permanent magnet Nd2Fe14B. Phys Rev B Condens Matter 1993; 48:6217-6224. [PMID: 10009165 DOI: 10.1103/physrevb.48.6217] [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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