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Bordelon MM, Liu C, Posthuma L, Kenney E, Graf MJ, Butch NP, Banerjee A, Calder S, Balents L, Wilson SD. Frustrated Heisenberg J1-J2 model within the stretched diamond lattice of LiYbO 2. Phys Rev B 2021; 103:10.1103/PhysRevB.103.014420. [PMID: 38486881 PMCID: PMC10938374 DOI: 10.1103/physrevb.103.014420] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/17/2024]
Abstract
We investigate the magnetic properties of LiYbO2, containing a three-dimensionally frustrated, diamond-like lattice via neutron scattering, magnetization, and heat capacity measurements. The stretched diamond network of Yb3+ ions in LiYbO2 enters a long-range incommensurate, helical state with an ordering wave vector k = ( 0.384 , ± 0.384 , 0 ) that "locks-in" to a commensurate k = ( 1 / 3 , ± 1 / 3,0 ) phase under the application of a magnetic field. The spiral magnetic ground state of LiYbO2 can be understood in the framework of a Heisenberg J 1 - J 2 Hamiltonian on a stretched diamond lattice, where the propagation vector of the spiral is uniquely determined by the ratio of J 2 / J 1 . The pure Heisenberg model, however, fails to account for the relative phasing between the Yb moments on the two sites of the bipartite lattice, and this detail as well as the presence of an intermediate, partially disordered, magnetic state below 1 K suggests interactions beyond the classical Heisenberg description of this material.
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Affiliation(s)
- Mitchell M. Bordelon
- Materials Department, University of California, Santa Barbara, California 93106, USA
| | - Chunxiao Liu
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - Lorenzo Posthuma
- Materials Department, University of California, Santa Barbara, California 93106, USA
| | - Eric Kenney
- Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467, USA
| | - M. J. Graf
- Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467, USA
| | - N. P. Butch
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Arnab Banerjee
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Purdue Quantum Science and Engineering Institute, Purdue University, West Lafayette IN - 47906
| | - Stuart Calder
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Leon Balents
- Kavli Institute for Theoretical Physics, University of California, Santa Barbara, Santa Barbara, California 93106, USA
| | - Stephen D. Wilson
- Materials Department, University of California, Santa Barbara, California 93106, USA
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Gofryk K, Saparov B, Durakiewicz T, Chikina A, Danzenbächer S, Vyalikh DV, Graf MJ, Sefat AS. Fermi-surface reconstruction and complex phase equilibria in CaFe2As2. Phys Rev Lett 2014; 112:186401. [PMID: 24856707 DOI: 10.1103/physrevlett.112.186401] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Indexed: 06/03/2023]
Abstract
Fermi-surface topology governs the relationship between magnetism and superconductivity in iron-based materials. Using low-temperature transport, angle-resolved photoemission, and x-ray diffraction, we show unambiguous evidence of large Fermi-surface reconstruction in CaFe2As2 at magnetic spin-density-wave and nonmagnetic collapsed-tetragonal (cT) transitions. For the cT transition, the change in the Fermi-surface topology has a different character with no contribution from the hole part of the Fermi surface. In addition, the results suggest that the pressure effect in CaFe2As2 is mainly leading to a rigid-band-like change of the valence electronic structure. We discuss these results and their implications for magnetism and superconductivity in this material.
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Affiliation(s)
- K Gofryk
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - B Saparov
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - T Durakiewicz
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - A Chikina
- Department of Physics, St. Petersburg State University, St. Petersburg 198504, Russia and Institute of Solid State Physics, Dresden University of Technology, Zellescher Weg 16, D-01062 Dresden, Germany
| | - S Danzenbächer
- Institute of Solid State Physics, Dresden University of Technology, Zellescher Weg 16, D-01062 Dresden, Germany
| | - D V Vyalikh
- Department of Physics, St. Petersburg State University, St. Petersburg 198504, Russia and Institute of Solid State Physics, Dresden University of Technology, Zellescher Weg 16, D-01062 Dresden, Germany
| | - M J Graf
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - A S Sefat
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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3
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Zhou C, Reichhardt C, Graf MJ, Su JJ, Balatsky AV, Beyerlein IJ. Comment on "Giant plasticity of a quantum crystal". Phys Rev Lett 2013; 111:119601. [PMID: 24074124 DOI: 10.1103/physrevlett.111.119601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Indexed: 06/02/2023]
Affiliation(s)
- C Zhou
- Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, Missouri 65409, USA
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Ronning F, Zhu JX, Das T, Graf MJ, Albers RC, Rhee HB, Pickett WE. Superconducting gap structure of the 115s revisited. J Phys Condens Matter 2012; 24:294206. [PMID: 22773378 DOI: 10.1088/0953-8984/24/29/294206] [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] [Indexed: 06/01/2023]
Abstract
Density functional theory calculations of the electronic structure of Ce- and Pu-based heavy fermion superconductors in the so-called 115 family are performed. The gap equation is used to consider which superconducting order parameters are most favorable assuming a pairing interaction that is peaked at (π, π, qz)—the wavevector for the antiferromagnetic ordering found in close proximity. In addition to the commonly accepted dx2−y2 order parameter, there is evidence that an extended s-wave order parameter with nodes is also plausible. We discuss whether these results are consistent with current observations and possible measurements that could help distinguish between these scenarios.
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Affiliation(s)
- F Ronning
- Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
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Pratt EJ, Hunt B, Gadagkar V, Yamashita M, Graf MJ, Balatsky AV, Davis JC. Interplay of Rotational, Relaxational, and Shear Dynamics in Solid
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He. Science 2011; 332:821-4. [DOI: 10.1126/science.1203080] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- E. J. Pratt
- Laboratory for Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853, USA
- Kavli Institute for Theoretical Physics, University of California, Santa Barbara, CA 93016, USA
| | - B. Hunt
- Laboratory for Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853, USA
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - V. Gadagkar
- Laboratory for Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853, USA
| | - M. Yamashita
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - M. J. Graf
- Theoretical Division and Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - A. V. Balatsky
- Theoretical Division and Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - J. C. Davis
- Laboratory for Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853, USA
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA
- School of Physics and Astronomy, University of St. Andrews, St. Andrews, Fife KY16 9SS, UK
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Bauer ED, Yang YF, Capan C, Urbano RR, Miclea CF, Sakai H, Ronning F, Graf MJ, Balatsky AV, Movshovich R, Bianchi AD, Reyes AP, Kuhns PL, Thompson JD, Fisk Z. Electronic inhomogeneity in a Kondo lattice. Proc Natl Acad Sci U S A 2011; 108:6857-6861. [PMCID: PMC3084059 DOI: 10.1073/pnas.1103965108] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2023] Open
Abstract
Inhomogeneous electronic states resulting from entangled spin, charge, and lattice degrees of freedom are hallmarks of strongly correlated electron materials; such behavior has been observed in many classes of d -electron materials, including the high-T c copper-oxide superconductors, manganites, and most recently the iron–pnictide superconductors. The complexity generated by competing phases in these materials constitutes a considerable theoretical challenge—one that still defies a complete description. Here, we report a manifestation of electronic inhomogeneity in a strongly correlated f -electron system, using CeCoIn5 as an example. A thermodynamic analysis of its superconductivity, combined with nuclear quadrupole resonance measurements, shows that nonmagnetic impurities (Y, La, Yb, Th, Hg, and Sn) locally suppress unconventional superconductivity, generating an inhomogeneous electronic “Swiss cheese” due to disrupted periodicity of the Kondo lattice. Our analysis may be generalized to include related systems, suggesting that electronic inhomogeneity should be considered broadly in Kondo lattice materials.
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Affiliation(s)
- E. D. Bauer
- Los Alamos National Laboratory, Los Alamos, NM 87545
| | - Yi-feng Yang
- Los Alamos National Laboratory, Los Alamos, NM 87545
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - C. Capan
- Department of Physics and Astronomy, University of California, Irvine, CA 92697
| | - R. R. Urbano
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32306
| | - C. F. Miclea
- Los Alamos National Laboratory, Los Alamos, NM 87545
| | - H. Sakai
- Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan; and
| | - F. Ronning
- Los Alamos National Laboratory, Los Alamos, NM 87545
| | - M. J. Graf
- Los Alamos National Laboratory, Los Alamos, NM 87545
| | | | - R. Movshovich
- Los Alamos National Laboratory, Los Alamos, NM 87545
| | - A. D. Bianchi
- Department de Physique, Universite de Montreal, Montreal, QC, Canada H3C 3J7
| | - A. P. Reyes
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32306
| | - P. L. Kuhns
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32306
| | | | - Z. Fisk
- Department of Physics and Astronomy, University of California, Irvine, CA 92697
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7
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Graf MJ, Balatsky AV, Nussinov Z, Grigorenko I, Trugman SA. Torsional oscillators and the entropy dilemma of putative supersolid4He. ACTA ACUST UNITED AC 2009. [DOI: 10.1088/1742-6596/150/3/032025] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Graf MJ, Lago J, Lascialfari A, Amato A, Baines C, Giblin SR, Lord JS, Tkachuk AM, Barbara B. Muon spin rotation studies of spin dynamics at avoided level crossings in LiY0.998Ho0.002F4. Phys Rev Lett 2007; 99:267203. [PMID: 18233602 DOI: 10.1103/physrevlett.99.267203] [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: 09/05/2007] [Indexed: 05/25/2023]
Abstract
We have studied the Ho3+ spin dynamics for LiY0.998Ho0.002F4 via the positive muon (mu+) transverse field depolarization rate lambdaTF as a function of temperature and magnetic field. We find sharp minima in lambdaTF(H) at fields for which the Ho3+ ion system has field-induced (avoided) level crossings. The reduction scales with calculated level repulsions, suggesting that mu+ depolarization by slow fluctuations of nonresonant Ho3+ spin states is partly suppressed when resonant tunneling opens new fluctuation channels at frequencies much greater than the muon precession frequency.
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Affiliation(s)
- M J Graf
- Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467, USA
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Young BL, Urbano RR, Curro NJ, Thompson JD, Sarrao JL, Vorontsov AB, Graf MJ. Microscopic evidence for field-induced magnetism in CeCoIn5. Phys Rev Lett 2007; 98:036402. [PMID: 17358701 DOI: 10.1103/physrevlett.98.036402] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2006] [Indexed: 05/14/2023]
Abstract
We present NMR data in the normal and superconducting states of CeCoIn5 for fields close to H(c2)(0)=11.8 T in the ab plane. Recent experiments identified a first-order transition from the normal to superconducting state for H>10.5 T, and a new thermodynamic phase below 290 mK within the superconducting state. We find that the Knight shifts of the In(1), In(2), and the Co are discontinuous across the first-order transition and the magnetic linewidths increase dramatically. The broadening differs for the three sites, unlike the expectation for an Abrikosov vortex lattice, and suggests the presence of static spin moments in the vortex cores. In the low-temperature and high-field phase, the broad NMR lineshapes suggest ordered local moments, rather than a long-wavelength quasiparticle spin density modulation expected for an FFLO phase.
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Affiliation(s)
- B-L Young
- Condensed Matter and Thermal Physics, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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10
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Ronning F, Hill RW, Sutherland M, Hawthorn DG, Tanatar MA, Paglione J, Taillefer L, Graf MJ, Perry RS, Maeno Y, Mackenzie AP. Thermal conductivity in the vicinity of the quantum critical end point in Sr3Ru2O7. Phys Rev Lett 2006; 97:067005. [PMID: 17026193 DOI: 10.1103/physrevlett.97.067005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2006] [Indexed: 05/12/2023]
Abstract
Thermal conductivity of Sr3Ru2O7 was measured down to 40 mK and at magnetic fields through the quantum critical end point at Hc=7.85 T. A peak in the electrical resistivity as a function of the field was mimicked by the thermal resistivity. In the limit as T-->0 K, we find that the Wiedemann-Franz law is satisfied to within 5% at all fields, implying that there is no breakdown of the electron despite the destruction of the Fermi liquid state at quantum criticality. A significant change in disorder [from rho0(H=0 T)=2.1 to 0.5 microOmega cm] does not influence our conclusions. At finite temperatures, the temperature dependence of the Lorenz number is consistent with ferromagnetic fluctuations causing the non-Fermi liquid behavior as one would expect at a metamagnetic quantum critical end point.
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Affiliation(s)
- F Ronning
- Department of Physics, University of Toronto, Toronto, Ontario, Canada
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11
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Curro NJ, Caldwell T, Bauer ED, Morales LA, Graf MJ, Bang Y, Balatsky AV, Thompson JD, Sarrao JL. Unconventional superconductivity in PuCoGa5. Nature 2005; 434:622-5. [PMID: 15800618 DOI: 10.1038/nature03428] [Citation(s) in RCA: 256] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2004] [Accepted: 02/04/2005] [Indexed: 11/08/2022]
Abstract
In the Bardeen-Cooper-Schrieffer theory of superconductivity, electrons form (Cooper) pairs through an interaction mediated by vibrations in the underlying crystal structure. Like lattice vibrations, antiferromagnetic fluctuations can also produce an attractive interaction creating Cooper pairs, though with spin and angular momentum properties different from those of conventional superconductors. Such interactions have been implicated for two disparate classes of materials--the copper oxides and a set of Ce- and U-based compounds. But because their transition temperatures differ by nearly two orders of magnitude, this raises the question of whether a common pairing mechanism applies. PuCoGa5 has a transition temperature intermediate between those classes and therefore may bridge these extremes. Here we report measurements of the nuclear spin-lattice relaxation rate and Knight shift in PuCoGa5, which demonstrate that it is an unconventional superconductor with properties as expected for antiferromagnetically mediated superconductivity. Scaling of the relaxation rates among all of these materials (a feature not exhibited by their Knight shifts) establishes antiferromagnetic fluctuations as a likely mechanism for their unconventional superconductivity and suggests that related classes of exotic superconductors may yet be discovered.
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Affiliation(s)
- N J Curro
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
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12
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Jeong IK, Graf MJ, Heffner RH. Effects of Bragg peak profiles and nanoparticle sizes on the real-space pair distribution function. J Appl Crystallogr 2005. [DOI: 10.1107/s0021889804025841] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
A study of the effects of Bragg peak profiles and nanoparticle size broadening on the real-space pair distribution function (PDF) is presented, using `synthetic' powder diffraction data. Bragg peak profiles from both asymmetric time-of-flight (TOF) spallation neutron data and symmetric synchrotron X-ray data are considered. Due to their asymmetric peak profiles, the TOF data cause artificial shifts of the PDF peak positions towards higher pair distances. Coupled with this effect is a broadening of the PDF peak widths due to aQ-dependent spectrometer resolution, making reliable refinement of thermal parameters difficult. These effects become more pronounced as theQresolution becomes worse. By contrast, the symmetric X-ray powder diffraction data do not cause a systematic shift of the PDF peak positions, and the broadening of the PDF peak widths has a relatively minor effect on the extraction of the thermal parameters. Finally, nanoparticle size broadening of the asymmetric neutron TOF powder diffraction data causes a shift of the PDF peak positions towards lowerrvalues and smears the PDF intensities from one atomic shell to another.
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13
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Jeong IK, Darling TW, Graf MJ, Proffen T, Heffner RH, Lee Y, Vogt T, Jorgensen JD. Role of the lattice in the gamma-->alpha phase transition of Ce: a high-pressure neutron and x-ray diffraction study. Phys Rev Lett 2004; 92:105702. [PMID: 15089217 DOI: 10.1103/physrevlett.92.105702] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2003] [Indexed: 05/24/2023]
Abstract
The temperature and pressure dependence of the thermal displacements and lattice parameters were obtained across the gamma-->alpha phase transition of Ce using high-pressure, high-resolution neutron and synchrotron x-ray powder diffraction. The estimated vibrational entropy change per atom in the gamma-->alpha phase transition, DeltaS(gamma-alpha)(vib) approximately (0.75+/-0.15)k(B), is about half of the total entropy change. The bulk modulus follows a power-law pressure dependence that is well described using the framework of electron-phonon coupling. These results clearly demonstrate the importance of lattice vibrations, in addition to the spin and charge degrees of freedom, for a complete description of the gamma-->alpha phase transition in elemental Ce.
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Affiliation(s)
- I-K Jeong
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
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14
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Demsar J, Averitt RD, Ahn KH, Graf MJ, Trugman SA, Kabanov VV, Sarrao JL, Taylor AJ. Quasiparticle relaxation dynamics in heavy fermion compounds. Phys Rev Lett 2003; 91:027401. [PMID: 12906507 DOI: 10.1103/physrevlett.91.027401] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2003] [Indexed: 05/24/2023]
Abstract
We present the first femtosecond studies of electron-phonon (e-ph) thermalization in heavy-fermion compounds. The e-ph thermalization time tau(ep) increases below the Kondo temperature by more than 2 orders of magnitude as T=0 K is approached. Analysis using the two-temperature model and numerical simulations based on Boltzmann's equations suggest that this anomalous slowing down of the e-ph thermalization derives from the large electronic specific heat and the suppression of scattering between heavy electrons and phonons.
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Affiliation(s)
- J Demsar
- Los Alamos National Laboratory, Mail Stop K764, Los Alamos, New Mexico 87545, USA
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Abstract
We study the dynamical spin susceptibility, chi(q,omega), in the normal and superconducting states of Sr(2)RuO(4). In the normal state, we find a peak in the vicinity of Q(i) approximately (0.72 pi,0.72 pi) in agreement with recent inelastic neutron scattering experiments. We predict that for spin triplet pairing in the superconducting state a resonance peak appears in the out-of-plane component of chi, but is absent in the in-plane component. In contrast, no resonance peak is expected for spin singlet pairing.
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Affiliation(s)
- D K Morr
- Theoretical Division, MS B262, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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17
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Graf MJ, Estrela P, Amato A, Baines C, Andreica D, Gygax FN, Schenck A. Magnetic quantum critical point and superconductivity in UPt3 doped with Pd. Phys Rev Lett 2000; 85:3005-3008. [PMID: 11005989 DOI: 10.1103/physrevlett.85.3005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2000] [Indexed: 05/23/2023]
Abstract
Transverse-field muon spin relaxation measurements have been carried out on the heavy-fermion superconductor UPt (3) doped with small amounts of Pd. We find that the critical Pd concentration for the emergence of the large-moment antiferromagnetic phase is approximately 0.6 at. %Pd. At the same Pd content, superconductivity is completely suppressed. The existence of a magnetic quantum critical point in the phase diagram, which coincides with the critical point for superconductivity, provides evidence for ferromagnetic spin-fluctuation mediated odd-parity superconductivity, which competes with antiferromagnetic order.
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Graf MJ, Yip SK, Sauls JA, Rainer D. Electronic thermal conductivity and the Wiedemann-Franz law for unconventional superconductors. Phys Rev B Condens Matter 1996; 53:15147-15161. [PMID: 9983313 DOI: 10.1103/physrevb.53.15147] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.3] [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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Palumbo M, Graf MJ. Electromagnetic absorption in an anisotropic layered superconductor. Phys Rev B Condens Matter 1996; 53:2261-2264. [PMID: 9983725 DOI: 10.1103/physrevb.53.2261] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Graf MJ, Palumbo M, Rainer D, Sauls JA. Infrared conductivity in layered d-wave superconductors. Phys Rev B Condens Matter 1995; 52:10588-10600. [PMID: 9980112 DOI: 10.1103/physrevb.52.10588] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Graf MJ, Rainer D, Sauls JA. Coupled two-dimensional Fermi liquids as a model for layered superconductors: Basic equations and elementary results. Phys Rev B Condens Matter 1993; 47:12089-12098. [PMID: 10005379 DOI: 10.1103/physrevb.47.12089] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [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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22
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Graf MJ, Huber TE, Huber CA. Superconducting properties of indium in the restricted geometry of porous Vycor glass. Phys Rev B Condens Matter 1992; 45:3133-3136. [PMID: 10001872 DOI: 10.1103/physrevb.45.3133] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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23
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Dietl T, Sawicki M, Dahl M, Heiman D, Isaacs ED, Graf MJ, Gubarev SI, Alov DL. Spin-flip scattering near the metal-to-insulator transition in Cd0.95Mn0.05Se:In. Phys Rev B Condens Matter 1991; 43:3154-3163. [PMID: 9997620 DOI: 10.1103/physrevb.43.3154] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Graf MJ, Richards CJ, Brown V, Meissner L, Dunaif A. The independent effects of hyperandrogenaemia, hyperinsulinaemia, and obesity on lipid and lipoprotein profiles in women. Clin Endocrinol (Oxf) 1990; 33:119-31. [PMID: 2205423 DOI: 10.1111/j.1365-2265.1990.tb00472.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We performed this study to clarify the independent effects of hyperandrogenaemia, hyperinsulinaemia, and obesity on lipid and lipoprotein levels in women with hyperandrogenaemia (HA) and anovulation which we designated as the polycystic ovary syndrome (PCO). We examined fasting lipid, lipoprotein, sex hormone and insulin levels in 38 women (21 obese (ob), 17 non-obese (nob] with HA and anovulation (PCO) and 38 normal ovulatory women (21 obese, 17 non-obese), matched for age and weight. The women with PCO had significantly increased androgen levels compared to the normal women. However, total oestradiol levels were similar in the PCO and normal women. Mean fasting insulin levels and 2-h glucose levels (both P less than 0.001) were significantly higher in ob PCO women. There were significant decreases (P less than or equal to 0.01) in high-density lipoprotein (HDL) levels in both the obese groups (ob PCO and ob normal) compared to the non-obese (nob PCO and nob normal) groups. Otherwise, mean lipid and lipoprotein levels did not differ in the ob or the nob PCO women compared to the control groups. The correlations between sex hormone, lipid and lipoprotein levels differed in the four groups of women. After statistical adjustment for potential hormonal interactions, nob PCO women had significant positive correlations between testosterone and LDL levels (R = 0.51, P less than 0.05) and insulin and TTG levels (R = 0.61, P less than 0.01). Ob normal women had a significant positive correlation between oestrone and TTG levels (R = 0.44, P less than or equal to 0.05). We conclude that (1) PCO women are in a low to risk for CVD primarily because of the increased prevalence of obesity rather than the reproductive hormone abnormalities associated with this disorder. However, by their lipid profiles, the PCO women were still in a low to intermediate risk group for CVD.
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Affiliation(s)
- M J Graf
- Department of Medicine, Mount Sinai School of Medicine, City University of New York, NY
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Fortune NA, Brooks JS, Graf MJ, Montambaux G, Chiang LY, Perenboom JA, Althof D. Specific-heat study of the anomalous quantum limit of (TMTSF)2ClO4. Phys Rev Lett 1990; 64:2054-2057. [PMID: 10041565 DOI: 10.1103/physrevlett.64.2054] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Davis OK, Bedford JM, Berkeley AS, Graf MJ, Rosenwaks Z. Pregnancy achieved through in vitro fertilization with cryopreserved semen from a man with Hodgkin's lymphoma. Fertil Steril 1990; 53:377-8. [PMID: 2298322 DOI: 10.1016/s0015-0282(16)53303-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- O K Davis
- Center for Reproductive Medicine and Infertility, Cornell University Medical College, New York, New York
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Graf MJ, Fortune NA, Brooks JS, Smith JL, Fisk Z. Specific heat of pure and thoriated UBe13 at low temperatures in high magnetic fields. Phys Rev B Condens Matter 1989; 40:9358-9361. [PMID: 9991441 DOI: 10.1103/physrevb.40.9358] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Graf MJ, Smith TP, Munekata H, Chang LL, Brooks JS. Carrier screening effects in semimetallic InAs single-quantum wells. Phys Rev B Condens Matter 1989; 40:5852-5855. [PMID: 9992639 DOI: 10.1103/physrevb.40.5852] [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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Goldberg BB, Heiman D, Graf MJ, Broido DA, Pinczuk A, Tu CW, English JH, Gossard AC. Optical transmission spectroscopy of the two-dimensional electron gas in GaAs in the quantum Hall regime. Phys Rev B Condens Matter 1988; 38:10131-10134. [PMID: 9945859 DOI: 10.1103/physrevb.38.10131] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
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Wiczyk HP, Janus CL, Richards CJ, Graf MJ, Gendal ES, Rabinowitz JG, Laufer N. Comparison of magnetic resonance imaging and ultrasound in evaluating follicular and endometrial development throughout the normal cycle. Fertil Steril 1988; 49:969-72. [PMID: 3286292 DOI: 10.1016/s0015-0282(16)59946-4] [Citation(s) in RCA: 51] [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: 01/05/2023]
Abstract
A prospective study was undertaken to evaluate and compare magnetic resonance imaging (MRI) and ultrasound (U/S) in monitoring follicular and endometrial development during the normal menstrual cycle. Results of MRI, U/S, estradiol (E2), and progesterone were obtained from five ovulatory volunteers on days 4, 8, 12, 16, 20, and 24 of the cycle. On U/S, all the women had only one dominant follicle, whereas MRI was able to detect a secondary cohort of follicles in three of five volunteers. Endometrial development on U/S and MRI showed similar patterns of growth with an increase on MRI from 5.8 +/- 1.1 mm on day 4 to a mean peak of 10.3 +/- 1.7 mm on day 24. A distinct feature of MRI was the demonstration of a junctional zone (JZ), which has a pattern of growth that resembles that of the endometrium, with accelerated growth from day 8 to day 16 (5.1 +/- .7 mm to 6.7 +/- .7 mm). The JZ corresponds anatomically to the distribution of the arcuate vessels and may therefore represent changes in blood supply to the endometrium. MRI, similar to U/S, is noninvasive and does not involve any radiation exposure but provides new information on uterine changes in the normal cycle. At present, its clinical applications are limited.
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Affiliation(s)
- H P Wiczyk
- Department of Obstetrics, Gynecology, and Reproductive Science, Mount Sinai Medical Center, New York, New York 10029
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Isaacs ED, Heiman D, Graf MJ, Goldberg BB, Kershaw R, Ridgley D, Dwight K, Wold A, Furdyna J, Brooks JS. Bound magnetic polarons below T=1 K. Phys Rev B Condens Matter 1988; 37:7108-7111. [PMID: 9943988 DOI: 10.1103/physrevb.37.7108] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
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Graf MJ, Reyniak JV, Battle-Mutter P, Laufer N. Histologic evaluation of the luteal phase in women following follicle aspiration for oocyte retrieval. Fertil Steril 1988; 49:616-9. [PMID: 2965032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The luteal phase was evaluated by endometrial biopsy (EMB) 11 to 13 days after administration of human chorionic gonadotropin (hCG) or initiation of the luteinizing hormone (LH) surge (hCG/LH) in 25 stimulated patients not undergoing embryo transfer (ET). Luteal phase defect (LPD) was defined as an EMB greater than 2 days out-of-phase when compared with the onset of subsequent menses. Nineteen women (76%) had LPDs ranging from 3 to 7 days. Mean estradiol (E2) on day of hCG/LH was significantly (P less than 0.01) higher (1709 +/- 997) in patients with in-phase EMBs than mean E2 levels in two groups of patients with out-of-phase EMBs (687 +/- 251, 941 +/- 366, respectively). These findings are further evidence of the importance of optimal follicular development to subsequent endometrial maturation.
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Affiliation(s)
- M J Graf
- Department of Obstetrics, Gynecology and Reproductive Science, Mount Sinai School of Medicine, New York, New York
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