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Naeini, J. G.; Chen, X. K.; Irwin, J. C.; Okuya, M.; Kimura, T.; Kishio, K.

doi:10.1103/physrevb.59.9642

Cited by 74 publications

(82 citation statements)

References 65 publications

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“…Being a two-particle probe, ERS is able to access the charge dynamics in both the normal and the superconducting states. 8,9,10,11 Moreover, through the use of particular sets of incident and scattered polarizations, it is able to probe different regions of the Fermi surface, i.e. the nodal (along the (0,0)-(π, π) direction) and antinodal (along the (0,0)-(π, 0) direction) quasiparticles.…”

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confidence: 99%

Interplay between the pseudogap and superconductivity in underdopedHgBa2CuO4+δsingle crystals

et al. 2005

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We report a doping dependant Electronic Raman Scattering (ERS) study of HgBa2CuO 4+δ (Hg-1201) single crystals. We investigate the dynamics of the antinodal and nodal quasiparticles. We show that the dynamical response of the antinodal quasiparticles is strongly reduced towards the underdoped regime in both the normal and superconducting states. When probing the nodal quasiparticles, we are able to distinguish between the energy scale of the pseudogap and that of the superconducting gap. A simple model relating the suppression of the dynamical response of the antinodal quasiparticles to fluctuations related to a competing phase is proposed.Among the unsolved problems of the high temperature superconductivity field, the question of the nature of the pseudogap phase is certainly the most highly debated. In particular its relationship with superconductivity remains an open question. One class of model attributes the pseudogap phase as a precursor phase of superconductivity in which Cooper pairs form at a temperature T * but only acquire phase coherence at a lower temperature T c where they form an uniform d-wave BCS condensate. 1 An important consequence of all these theories is that the pseudogap and the superconducting gap are intimately connected: they can be both identified to a pairing energy. This approach is supported by ARPES data which show that the pseudogap and the superconducting gap open in the same region of the Fermi surface, 2 i.e. close to the (π,0) and related points. Another class of models invokes various phases which are not directly related to superconductivity but rather compete with it. Among the proposed phases we find a precursor SDW phase, 3 a d-density wave phase 4 or an orbital current phase. 5 Most of these theories, but not all, predict the presence of a quantum critical point somewhere near the optimally doped regime. 6,7 Specific heat data, doping evolution of the superfluid density and impurity induced T c suppression, among others, have been interpreted as evidences for this scenario. 6 In order to fully understand the nature of the pseudogap, a two-particle response function able to probe quasiparticle dynamics on different regions of the Brillouin zone would be useful. In this report we show that Electronic Raman Scattering (ERS) is such a probe and report a doping dependant study of the interplay between the pseudogap and superconductivity in HgBa 2 CuO 4+δ (Hg-1201) single crystals. Being a two-particle probe, ERS is able to access the charge dynamics in both the normal and the superconducting states. 8,9,10,11 Moreover, through the use of particular sets of incident and scattered polarizations, it is able to probe different regions of the Fermi surface, i.e. the nodal (along the (0,0)-(π, π) direction) and antinodal (along the (0,0)-(π, 0) direction) quasiparticles. With this unique ability, ERS is thus expected to give important information on the pseudogap nature which are not accessible via one-particle probes such as ARPES.With only one CuO 2 plane per unit cell and a pur...

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Interplay between the pseudogap and superconductivity in underdopedHgBa2CuO4+δsingle crystals

et al. 2005

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“…In the B 1g channel the intensity of the pair-breaking peak decreases continuously when approaching the underdoped range of the phase diagram which goes along with a strong suppression of the overall Raman intensity. This effect may be caused by a change of the Fermi surface (FS) topology and is also seen in YBa 2 Cu 3 O 6+x [1] and La 2−x Sr x CuO 4 [2]. The low frequency behavior of the SC spectra is shown in Fig.…”

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Superconducting gap and pseudogap in Bi-2212

Opel

Venturini

Hackl

et al. 2000

Physica B: Condensed Matter

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We present results of Raman scattering experiments in differently doped Bi2Sr2(CaxY1−x)Cu2O 8+δ (Bi-2212) single crystals. Below Tc the spectra show pair-breaking features in the whole doping range reflecting a d x 2 −y 2 order parameter. In the normal state between Tc and T * ≃ 200K we find evidence for a pseudogap in B2g symmetry. Upon doping its effect on the spectra decreases while its energy scale appears to be unchanged. The relationship between the superconducting (SC) and the pseudogap (PG) phases and their evolution with doping is of particular interest for understanding the cuprates. In the following we will describe recent results from light scattering experiments in Bi 2 Sr 2 (Ca x Y 1−x )Cu 2 O 8+δ (Bi-2212) single crystals. The experiments were performed in pseudo back-scattering geometry using a standard Raman set-up. Figure 1 shows spectra from Bi-2212 at three different doping levels as a function of temperature. The raw data have been divided by the Bose factor in order to obtain the Raman response Imχ(ω, T ). In the SC state the well-known pair-breaking peaks (marked with vertical arrows) can be found in both B 1g (a-c) and B 2g (d-f) symmetry for high and optimal doping whereas in the underdoped material this feature is only present in B 2g symmetry. The peak frequencies in the B 2g channel and thus the 1 Corresponding author. E-mail: opel@badw.de energy scales of the SC correlations depend on the doping level and scale with the transition temperature T c . In the B 1g channel the intensity of the pair-breaking peak decreases continuously when approaching the underdoped range of the phase diagram which goes along with a strong suppression of the overall Raman intensity. This effect may be caused by a change of the Fermi surface (FS) topology and is also seen in YBa 2 Cu 3 O 6+x [1] and La 2−x Sr x CuO 4 [2]. The low frequency behavior of the SC spectra is shown in Fig. 1 (g-i) in a double logarithmic representation. In the B 2g channel the intensities increase almost linearly over a large frequency range while in B 1g we find a cross-over from linear to cubic behavior. These characteristic power laws are strong evidence for d x 2 −y 2 wave pairing [3] in the whole doping range.In the normal state at temperatures between T * ≃ 200K and T c the B 2g response shows new features: Spectral weight is lost within an intermediate, doping-independent frequency interval

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“…Both appear at nearly the same energy, exhibit similar doping dependence and possibly have the same physical origin. [4,5,9,10] It is interesting also to note that in the materials where the MIR peak appears at a relatively small energy, comparable with the typical damping energy Σ ≡ /τ [7,8], there is an essential difference between the predictions of the usual one-band optical models and measurements. It is explicitly shown that the development of the measured MIR structure with temperature can be fitted well with the orbital Kondo model of Emery and Kivelson [19] (representing the regime where ω ir peak ≈ Σ) rather than with the mentioned one-band models (underdamped regime: ω ir peak is proportional to characteristic correlation energy scales, such as the Hubbard interaction U [11,12] or the AF exchange energy J [13]).…”

Section: Introductionmentioning

confidence: 99%

“…The latter is also accompanied by several anomalies regarding the relative spectral weights of three Raman polarizations. [3,9,10] Actually, the recent interest in the Drude part of the optical conductivity and Raman scattering spectra of the underdoped compounds is stimulated by the clear evidence for important role of the normal-state coherence effects. The optical conductivity and B 2g Raman spectra scan the electronic states in the nodal region of the Fermi surface (so-called "cold spots" on the Fermi surface: k x = k y ), while the A 1g and B 1g Raman scattering processes probe the electronic states in the vicinity of the van Hove points ("hot spots").…”

Section: Introductionmentioning

confidence: 99%

“…Anomalous low-frequency structures related to the superconducting (SC) pseudogap, the antiferromagnetic (AF) pseudogap, the two-magnon excitations or the density waves are observed in the latter crystals, usually in one or two (of four) "optical" channels (optical conductivity and A 1g , B 1g and B 2g Raman symmetries). [3,4,5,6,7,8,9,10] Any theory of the low-frequency excitations in the underdoped cuprates should explain anomalies in both optical conductivity and Raman scattering spectra, taking the normal-state coherence effects properly into account.…”

Section: Introductionmentioning

confidence: 99%

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