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Takigawa, Masaharu; Reyes, A. P.; Hammel, P. C.; Thompson, J. D.; Heffner, R. H.; Fisk, Z.; Ott, K.

doi:10.1103/physrevb.43.247

Cited by 692 publications

(357 citation statements)

References 31 publications

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“…By combining the results in Figs. 1 and 2 with the pseudogap behavior which was then-noticed in NMR (spin gap) [42,43] and c-axis conductivity [44] (insulating below T * ) studies, we proposed a picture shown in Fig. 3(b) in 1994 [6,7] to map the situation of the cuprates to BE-BCS crossover.…”

Section: Be-bcs Crossover Conjecturementioning

confidence: 99%

Condensation, excitation, pairing, and superfluid density in high-T_c superconductors: the magnetic resonance mode as a roton analogue and a possible spin-mediated pairing

Uemura¹

2004

J. Phys.: Condens. Matter

123

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To find out a primary determing factor of Tc and a pairing mechanism in high-Tc cuprates, we combine the muon spin relaxation results on ns/m * (superconducting carrier density / effective mass), accumulated over the last 15 years, with the results from neutron and Raman scattering, STM, specific heat, Nernst effect and ARPES measurements. We identify the neutron magnetic resonance mode as an analogue of roton minimum in the superfluid 4 He, and argue that ns/m * and the resonance mode energy ωres play a primary role in determining Tc in the underdoped region. We propose a picture that roton-like excitations in the cuprates appear as a coupled mode, which has the resonance mode for spin and charge responses at different momentum transfers but the same energy transfers, as detected respectively, by the neutron S=1 mode and the Raman S=0 A1g mode. We shall call this as the "hybrid spin/charge roton". After discussing the role of dimensionality in condensation, we propose a generic phase diagram of the cuprates with spatial phase separation in the overdoped region as a special case of the BE-BCS crossover conjecture where the superconducting coupling is lost rapidly in the overdoped region. Using a microscopic model of charge motion resonating with antiferomagnetic spin fluctuations, we propose a possibility that the hybrid spin/charge roton and higher-energy spin fluctuations mediate the superconducting pairing. In this model, the resonance modes can be viewed as a meson-analogue and the "dome" shape of the phase diagram can be understood as a natural consequence of departure from the competing Mott insulator ground state via carrier doping.

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Section: Be-bcs Crossover Conjecturementioning

confidence: 99%

Condensation, excitation, pairing, and superfluid density in high-T_c superconductors: the magnetic resonance mode as a roton analogue and a possible spin-mediated pairing

Uemura¹

2004

J. Phys.: Condens. Matter

123

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“…1, 2, 3, 4, 5, 6, 7) Minutely speaking, the different behaviors of 1/T 2G have been reported for different High-T c compounds. 3,4,6,7) There is an idea that attributes the difference to the effects of the interlayer coupling. 4,7) The results of the single layer compounds show the decrease of 1/T 2G in the pseudogap state.…”

Section: /Tmentioning

confidence: 99%

“…19,22,23,24,25,26,27,28,29,30,31,32,33,34,3 They are classified into some kinds. The scenario based on the phase fluctuations has been proposed by Emery and Kivelson 21) and calculated by other authors.…”

Section: §1 Introductionmentioning

confidence: 99%

Pseudogap Phenomena and Superconducting Fluctuations in Hubbard Model for High-T_cCuprates

2001

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The pseudogap phenomena in High-Tc cuprates are investigated on the basis of the Hubbard model which includes only the on-site repulsive interaction U . We consider the pairing scenario for the pseudogap. The pseudogap arises from the resonance scattering due to the strong superconducting fluctuations. First, the electronic state and the anti-ferromagnetic spin fluctuations are calculated by using the fluctuation exchange (FLEX) approximation. The T-matrix which is the propagator of the superconducting fluctuations is calculated by extending theÉliashberg equation. The characteristics of the superconducting fluctuations due to the pairing interaction arising from the spin fluctuations are represented in the T-matrix. The self-energy due to the superconducting fluctuations is calculated by the T-matrix approximation. The pseudogap is shown in the single particle properties and the magnetic properties. Moreover, a comprehensive explanation of the doping dependence of the pseudogap is obtained. Furthermore, we apply the theory to the electron-doped cuprates and obtain the consistent results with the recent experiments. Finally, the self-consistent calculation for the spin fluctuations, superconducting fluctuations and the single particle properties are carried out within the FLEX and the self-consistent T-matrix approximations. The relation between the superconducting fluctuations and the spin fluctuations are clarified. The calculated superconducting critical temperature Tc is remarkably reduced from the results of the mean field (FLEX) calculation. In particular, it is shown that the critical temperature decreases with decreasing doping in the under-doped region with large U . The pseudogap phenomena in under-doped High-T c cuprates have been interested for many years. The pseudogap is considered to be a key issue for the comprehensive understanding of the High-T c superconductivity.The pseudogap phenomena mean the suppression of the spectral weight above T c without any long range order. They are universal phenomena observed in various compounds of High-T c cuprates in the under-doped region. First, the pseudogap was found in the magnetic excitation channel by the nuclear magnetic resonance (NMR) experiment. 1) At present, the pseudogap phenomena have been observed in various quantities which include NMR, 1, 2, 3, 4, 5, 6, 7) neutron scattering, 8) transport, 9, 10) optical spectrum, 11) electronic specific heat, 12) density of states 13) and the single particle spectral weight. 14) The experimental results are reviewed in ref. 15.There are many theoretical scenarios proposed for the pseudogap phenomena. An important one is the resonating valence bond (RVB) theory. The RVB theory is an approach from the non-Fermi liquid state and attributes the pseudogap to the singlet pairing of the spinons. 16) As an approach from the Fermi liquid state, the magnetic * E-mail: yanase@hosi.phys.s.u-tokyo.ac.jp * * Present address: Department of Physics, University of Tokyo, Tokyo 113-0033 scenario has been investigated. 17,18) ...

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“…The latter slightly deviates from linearity above T c , evidencing the presence of weak magnetic correlations [41,42]. Additionally, the optimally doped and weakly overdoped compounds display a hump in the spin-lattice relaxation rate, above T c [6,9], when the magnetic field is oriented in-plane (H ⊥ c).…”

Section: Discussionmentioning

confidence: 99%

Persistence of slow fluctuations in the overdoped regime of Ba(Fe1-xRhx)2As2 superconductors

Bossoni

Moroni

Julien

et al. 2016

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We present nuclear magnetic resonance evidence that very slow ( 1 MHz) spin fluctuations persist into the overdoped regime of Ba(Fe 1−x Rh x ) 2 As 2 superconductors. Measurements of the 75 As spin echo decay rate, obtained both with Hahn Echo and Carr Purcell Meiboom Gill pulse sequences, show that the slowing down of spin fluctuations can be described by short-range diffusive dynamics, likely involving domain walls motions separating (π/a,0) from (0,π/a) correlated regions. This slowing down of the fluctuations is weakly sensitive to the external magnetic field and, although fading away with doping, it extends deeply into the overdoped regime.

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Cu and O NMR studies of the magnetic properties ofYBa2Cu3

Cited by 692 publications

References 31 publications

Condensation, excitation, pairing, and superfluid density in high-T_c superconductors: the magnetic resonance mode as a roton analogue and a possible spin-mediated pairing

Condensation, excitation, pairing, and superfluid density in high-T_c superconductors: the magnetic resonance mode as a roton analogue and a possible spin-mediated pairing

Pseudogap Phenomena and Superconducting Fluctuations in Hubbard Model for High-T_cCuprates

Persistence of slow fluctuations in the overdoped regime of Ba(Fe<sub>1-x</sub>Rh<sub>x</sub>)<sub>2</sub>As<sub>2</sub> superconductors

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Cu and O NMR studies of the magnetic properties ofYBa2Cu3

Cited by 692 publications

References 31 publications

Condensation, excitation, pairing, and superfluid density in high-Tc superconductors: the magnetic resonance mode as a roton analogue and a possible spin-mediated pairing

Condensation, excitation, pairing, and superfluid density in high-Tc superconductors: the magnetic resonance mode as a roton analogue and a possible spin-mediated pairing

Pseudogap Phenomena and Superconducting Fluctuations in Hubbard Model for High-TcCuprates

Persistence of slow fluctuations in the overdoped regime of Ba(Fe<sub>1-x</sub>Rh<sub>x</sub>)<sub>2</sub>As<sub>2</sub> superconductors

Contact Info

Product

Resources

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Condensation, excitation, pairing, and superfluid density in high-T_c superconductors: the magnetic resonance mode as a roton analogue and a possible spin-mediated pairing

Condensation, excitation, pairing, and superfluid density in high-T_c superconductors: the magnetic resonance mode as a roton analogue and a possible spin-mediated pairing

Pseudogap Phenomena and Superconducting Fluctuations in Hubbard Model for High-T_cCuprates