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Maurice R, Pradipto AM, Guihéry N, Broer R, de Graaf C. Antisymmetric Magnetic Interactions in Oxo-Bridged Copper(II) Bimetallic Systems. J Chem Theory Comput 2010; 6:3092-101. [DOI: 10.1021/ct100329n] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- R. Maurice
- Laboratoire de Chimie et Physique Quantiques, Université de Toulouse 3, 118, route de Narbonne, 31062 Toulouse France, Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Marcel·lí Domingo s/n, 43007 Tarragona, Spain, Zernike Institute for Advanced Materials, University of Groningen, Groningen 9747AG, The Netherlands, and Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluis Companys 23, 08010, Barcelona, Spain
| | - A. M. Pradipto
- Laboratoire de Chimie et Physique Quantiques, Université de Toulouse 3, 118, route de Narbonne, 31062 Toulouse France, Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Marcel·lí Domingo s/n, 43007 Tarragona, Spain, Zernike Institute for Advanced Materials, University of Groningen, Groningen 9747AG, The Netherlands, and Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluis Companys 23, 08010, Barcelona, Spain
| | - N. Guihéry
- Laboratoire de Chimie et Physique Quantiques, Université de Toulouse 3, 118, route de Narbonne, 31062 Toulouse France, Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Marcel·lí Domingo s/n, 43007 Tarragona, Spain, Zernike Institute for Advanced Materials, University of Groningen, Groningen 9747AG, The Netherlands, and Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluis Companys 23, 08010, Barcelona, Spain
| | - R. Broer
- Laboratoire de Chimie et Physique Quantiques, Université de Toulouse 3, 118, route de Narbonne, 31062 Toulouse France, Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Marcel·lí Domingo s/n, 43007 Tarragona, Spain, Zernike Institute for Advanced Materials, University of Groningen, Groningen 9747AG, The Netherlands, and Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluis Companys 23, 08010, Barcelona, Spain
| | - C. de Graaf
- Laboratoire de Chimie et Physique Quantiques, Université de Toulouse 3, 118, route de Narbonne, 31062 Toulouse France, Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Marcel·lí Domingo s/n, 43007 Tarragona, Spain, Zernike Institute for Advanced Materials, University of Groningen, Groningen 9747AG, The Netherlands, and Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluis Companys 23, 08010, Barcelona, Spain
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Lindgård PA. Spiral spin state in high-temperature copper-oxide superconductors: evidence from neutron scattering measurements. PHYSICAL REVIEW LETTERS 2005; 95:217001. [PMID: 16384170 DOI: 10.1103/physrevlett.95.217001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2005] [Indexed: 05/05/2023]
Abstract
An effective spiral spin phase ground state provides a new paradigm for the high-temperature superconducting cuprates. It accounts for the recent neutron scattering observations of spin excitations regarding both the energy dispersion and the intensities, including the "universal" rotation by 45 degrees around the resonance energy . The intensity has a 2D character even in a single twin crystal. The value of is related to the nesting properties of the Fermi surface. The excitations above are shown to be due to in-plane spin fluctuations, a testable difference from the stripe model. The form of the exchange interaction function reveals the effects of the Fermi surface, and the unique shape predicts large quantum spin fluctuations in the ground state.
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Affiliation(s)
- Per-Anker Lindgård
- Materials Research Department, Risø National Laboratory, 4000 Roskilde, Denmark.
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Harris AB, Yildirim T, Aharony A, Entin-Wohlman O, Korenblit IY. Unusual symmetries in the Kugel-Khomskii Hamiltonian. PHYSICAL REVIEW LETTERS 2003; 91:087206. [PMID: 14525275 DOI: 10.1103/physrevlett.91.087206] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2002] [Indexed: 05/24/2023]
Abstract
The Kugel-Khomskii Hamiltonian for cubic titanates describes spin and orbital superexchange interactions between d(1) ions having threefold degenerate t(2g) orbitals. Since orbitals do not couple along "inactive" axes, perpendicular to the orbital planes, the total number of electrons in |alpha> orbitals in any such plane and the corresponding total spin are both conserved. A Mermin-Wagner construction shows that there is no long-range spin ordering at nonzero temperatures. Inclusion of spin-orbit coupling allows such ordering, but even then the excitation spectrum is gapless due to a continuous symmetry. Thus, the observed order and gap require more symmetry breaking terms.
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Affiliation(s)
- A B Harris
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA
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Kataev V, Choi KY, Grüninger M, Ammerahl U, Büchner B, Freimuth A, Revcolevschi A. Strong anisotropy of superexchange in the copper-oxygen chains of La(14)-xCaxCu24O41. PHYSICAL REVIEW LETTERS 2001; 86:2882-2885. [PMID: 11290063 DOI: 10.1103/physrevlett.86.2882] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2000] [Indexed: 05/23/2023]
Abstract
Electron spin resonance data of Cu2+ ions in La(14)-xCaxCu24O41 single crystals (x = 9,11,12) reveal a very large width of the resonance line in the paramagnetic state. This signals an unusually strong anisotropy of approximately 10% of the isotropic Heisenberg superexchange in the Cu-O chains of this compound. The strong anisotropy can be explained by the specific geometry of two symmetrical 90 degrees Cu-O-Cu bonds, which boosts the importance of orbital degrees of freedom. Our data show the apparent limitations of the applicability of an isotropic Heisenberg model to the low-dimensional cuprates.
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Affiliation(s)
- V Kataev
- II. Physikalisches Institut, Universität zu Köln, 50937 Köln, Germany
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