Local Ordering in the Pseudogap State of the High-
 T
 c
 Superconductor Bi
 2
 Sr
 2
 CaCu
 2
 O
 8+δ

Vershinin, Michael; Misra, Shashank; Ono, Shimpei; Abe, Yasushi; Ando, Yoichi; Yazdani, Ali

doi:10.1126/science.1093384

Cited by 500 publications

(482 citation statements)

References 30 publications

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“…Angle-resolved photoemission (ARPES) shows that the pseudogap opens in the antinodal region near ð0; πÞ (we set the lattice constant a to unity), leaving behind ungapped "Fermi arcs" centered around the nodes. Recent x-ray scattering data [2][3][4][5] reveal that the pseudogap is likely to be a distinct phase, characterized by the onset of a charge density wave (CDW) with wave vectors at ð0; AEδÞ and ðAEδ; 0Þ, where δ decreases with increasing doping, thus confirming evidence for charge order found earlier by scanning tunneling microscope (STM) [6][7][8][9] and nuclear magnetic resonance (NMR) experiments [10]. Recent advances include STM and x-ray studies on the same Bi 2 Sr 2 CaCu 2 O 8þx (Bi-2212) samples [11].…”

supporting

confidence: 76%

Amperean Pairing and the Pseudogap Phase of Cuprate Superconductors

2014

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The enigmatic pseudogap phase in underdoped cuprate high-T c superconductors has long been recognized as a central puzzle of the T c problem. Recent data show that the pseudogap is likely a distinct phase, characterized by a medium range and quasistatic charge ordering. However, the origin of the ordering wave vector and the mechanism of the charge order is unknown. At the same time, earlier data show that precursive superconducting fluctuations are also associated with this phase. We propose that the pseudogap phase is a novel pairing state where electrons on the same side of the Fermi surface are paired, in strong contrast with conventional Bardeen-Cooper-Schrieffer theory which pairs electrons on opposite sides of the Fermi surface. In this state the Cooper pair carries a net momentum and belongs to a general class called pair density wave. The microscopic pairing mechanism comes from a gauge theory formulation of the resonating valence bond (RVB) picture, where spinons traveling in the same direction feel an attractive force in analogy with Ampere's effects in electromagnetism. We call this Amperean pairing.Charge order automatically appears as a subsidiary order parameter even when long-range pair order is destroyed by phase fluctuations. Our theory gives a prediction of the ordering wave vector which is in good agreement with experiment. Furthermore, the quasiparticle spectrum from our model explains many of the unusual features reported in photoemission experiments. The Fermi arc, the unusual way the tip of the arc terminates, and the relation of the spanning vector of the arc tips to the charge ordering wave vector also come out naturally. Finally, we propose an experiment that can directly test the notion of Amperean pairing. DOI: 10.1103/PhysRevX.4.031017 Subject Areas: Condensed Matter Physics, SuperconductivitySince the early days of cuprate superconductivity research, the pseudogap phase has been identified as a central piece of the high-T c puzzle [1]. The pseudogap opens below a temperature T Ã much above T c in underdoped cuprates, and it is visible in the spin susceptibility as detected by the Knight shift, in tunneling spectroscopy and in c-axis conductivity. Angle-resolved photoemission (ARPES) shows that the pseudogap opens in the antinodal region near ð0; πÞ (we set the lattice constant a to unity), leaving behind ungapped "Fermi arcs" centered around the nodes. Recent x-ray scattering data [2][3][4][5] reveal that the pseudogap is likely to be a distinct phase, characterized by the onset of a charge density wave (CDW) with wave vectors at ð0; AEδÞ and ðAEδ; 0Þ, where δ decreases with increasing doping, thus confirming evidence for charge order found earlier by scanning tunneling microscope (STM) [6][7][8][9] and nuclear magnetic resonance (NMR) experiments [10]. Recent advances include STM and x-ray studies on the same Bi 2 Sr 2 CaCu 2 O 8þx (Bi-2212) samples [11]. Other signatures include Kerr rotation [12], the emergence of anisotropy in the Nernst effect, etc. [13]. (Another set of exp...

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supporting

confidence: 76%

Amperean Pairing and the Pseudogap Phase of Cuprate Superconductors

2014

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“…We next turn to the underdoped Bi 2212, which has been intensively studied by ARPES (angle-resolved photoemission spectroscopy) [60,61] and STM (scanning tunneling microscopy) [62,63] because the crystals can be cleaved cleanly. Nernst results on this system are particularly valuable.…”

Section: Underdoped Cupratesmentioning

confidence: 99%

Nernst effect in high-Tcsuperconductors

2006

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The observation of a large Nernst signal eN in an extended region above the critical temperature Tc in hole-doped cuprates provides evidence that vortex excitations survive above Tc. The results support the scenario that superfluidity vanishes because long-range phase coherence is destroyed by thermally-created vortices (in zero field), and that the pair condensate extends high into the pseudogap state in the underdoped (UD) regime. We present a series of measurements to high fields H which provide strong evidence for this phase-disordering scenario. Measurements of eN in fields H up to 45 T reveal that the vortex Nernst signal has a characteristic "tilted-hill" profile, which is qualitatively distinct from that of quasi-particles. The hill profile, which is observed above and below Tc, underscores the continuity between the vortex-liquid state below Tc and the Nernst region above Tc. The upper critical field (depairing field) Hc2 determined by the hill profile (in slightly UD to overdoped samples) displays an anomalously weak T dependence, which is consistent with the phase-disordering scenario. We contrast the Nernst results and Hc2 behavior in hole-doped and electron-doped cuprates. Contour plots of eN (T, H) in the T -H plane clearly bring out the continuous extension of the low-T vortex liquid state into the the high-T Nernst region in holedoped cuprates (but not in the electron-doped cuprate). The existence of an enhanced diamagnetic magnetization M that survives to intense H above Tc is obtained from torque magnetometry. The observed M scales accurately like eN above Tc, confirming that the large Nernst signal is associated with local diamagnetic supercurrents that persist above Tc. We emphasize implications of the new features in the phase diagram implied by the high-field results, and discuss several theories.

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“…(d) The "gap-map" obtained by STM in moderately underdoped Bi2212 [10,11]. The red-yellow regions represent the area where the sharp superconducting gap is observed, while blue and black region has a response similar to those found in the "pseudogap" region [68] or the nonsuperconducting very underdoped region [69]. The characteristic length scale for this spontaneous formation of spatial heterogeneity is comparable to the coherence length ξ ab .…”

Section: Acknowledgmentmentioning

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

100

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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Local Ordering in the Pseudogap State of the High- T _c Superconductor Bi ₂ Sr ₂ CaCu ₂ O _8+δ

Cited by 500 publications

References 30 publications

Amperean Pairing and the Pseudogap Phase of Cuprate Superconductors

Amperean Pairing and the Pseudogap Phase of Cuprate Superconductors

Nernst effect in high-Tcsuperconductors

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

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Local Ordering in the Pseudogap State of the High- T c Superconductor Bi 2 Sr 2 CaCu 2 O 8+δ

Cited by 500 publications

References 30 publications

Amperean Pairing and the Pseudogap Phase of Cuprate Superconductors

Amperean Pairing and the Pseudogap Phase of Cuprate Superconductors

Nernst effect in high-Tcsuperconductors

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

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Product

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Local Ordering in the Pseudogap State of the High- T _c Superconductor Bi ₂ Sr ₂ CaCu ₂ O _8+δ

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