Optical studies of charge dynamics in optimally doped<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Bi</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Sr</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">CaCu</mml:mi></mml:mrow><mml:mrow><mml:mn

Tu, Jiajing; Homes, C. C.; Gu, Genda; Basov, D. N.; Strongin, Myron

doi:10.1103/physrevb.66.144514

Cited by 67 publications

(118 citation statements)

References 26 publications

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“…In addition, measurements performed on optimally doped single crystal Bi 2 Sr 2 CaCu 2 O 8+x measured at 10.5, 5.25, and 3.0 meV when analyzed with Eq. 2 demonstrate a temperature and frequency independent Hall mass 8 consistent with ARPES, 10 the optical mass derived from ac conductivity, 11 and the Hall mass derived from near-infrared Hall measurements.…”

mentioning

confidence: 72%

Terahertz magnetotransport measurements in underdopedPr2−xCexCuO4and comparison with angle-resolved phot

et al. 2009

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We present magneto-transport measurements performed on underdoped Pr2−xCexCuO4 at THz frequencies as a function of temperature and doping. A rapidly decreasing Hall mass is observed as the doping is reduced consistent with the formation of small electron Fermi pockets. However, both dc and infrared (IR) magneto-transport data strongly deviate from the predictions of transport theory in the relaxation time approximation (RTA) based on angular resolved photoemission data. The Hall mass is observed to increase continuously with increasing temperature with no signature at the Néel temperature. In the paramagnetic state, the temperature dependence of the Hall mass is consistent with current vertex corrections to the Hall conductivity due to magnetic fluctuations as observed in overdoped Pr2−xCexCuO4. Possible causal mechanisms for the discrepancy between transport theory within the RTA and the magneto-transport data are discussed.

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mentioning

confidence: 72%

Terahertz magnetotransport measurements in underdopedPr2−xCexCuO4and comparison with angle-resolved phot

et al. 2009

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“…The 100 K spectrum does not display the sharp onset around 700 cm −1 discussed above. Nevertheless, at low frequencies it deviates slightly from the straight line that can be used to approximate [1/τ ](ω) in the region between ca 1000 cm −1 and 2500 cm −1 , an effect similar to the one of some experimental spectra 25,26,29,54 . Obviously, this kind of deviation does not simply imply the presence of a sharp mode.…”

Section: E Role Of the Spin-fluctuation Continuummentioning

confidence: 85%

“…The latter allows us to consider derivatives of [1/τ ](ω) instead of those of σ 1 (ω) when searching for the singularities. Recently, it has become popular 26,31,55,56,57,58 to use the function W (ω) of Eq. 6 which is related to [1/τ ] as…”

Section: Resultsmentioning

confidence: 99%

Interpretation of in-plane infrared response of high-Tccuprate superconductors involving spin fluctuations using quasiparticle spectral functions

et al. 2005

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The in-plane infrared response of the high-Tc cuprate superconductors was studied using the spin-fermion model, where charged quasiparticles of the copper-oxygen planes are coupled to spin fluctuations. First, we analyzed structures of the superconducting-state conductivity reflecting the coupling of the quasiparticles to the resonance mode observed by neutron scattering. The conductivity σ computed with the input spin susceptibility in the simple form of the mode exhibits two prominent features: an onset of the real part of σ starting around the frequency ω0 of the mode and a maximum of a related function W (ω), roughly proportional to the second derivative of the scattering rate [1/τ ](ω), centered approximately at ω = ω0 + ∆0/h, where ∆0 is the maximum value of the superconducting gap. The two structures are well known from earlier studies. Their physical meaning, however, has not been sufficiently elucidated thus far. Our analysis involving quasiparticle spectral functions provides a clear interpretation. Second, we explored the role played by the spin-fluctuation continuum, whose spectral weight is known to be much larger than the one of the mode. We have shown that the experimental spectra of 1/τ can be approximately reproduced by augmenting the resonant-mode component of the spin susceptibility by a suitable continuum component with a considerably higher spectral weight and with a characteristic width of several hundreds meV. The computed spectra of 1/τ display a new structure in the mid-infrared which is related to the finite width of the occupied part of the conduction band. Third, we investigated the temperature dependence (TD) of σ assuming that the normal state spin susceptibility consists of an overdamped low energy mode and the continuum component. The differences between the experimental normal-state spectra and those of the superconducting state, including some interesting effects at higher frequencies, are reasonably well reproduced. Motivated by recent experimental 304, 708 (2004).], we further studied the TDs of the effective kinetic energy K.E. and of the intraband spectral weight IO. Calculations for the trivial case of noninteracting quasiparticles in the normal state and a BCS-like superconducting state reveal a strong sensisitivity of the TD of IO to details of the dispersion relation. The TDs of K.E. and IO in the interacting case, for the set of the values of the input parameters used throughout this work, are similar to those of the trivial case. The physics beyond the changes occuring when going from the normal to the superconducting state, however, is shown to be more complex, involving, besides the formation of the gap, also a feedback effect of the spin fluctuations on the quasiparticles and a significant shift of the chemical potential.I.

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“…In Fig.30 we compare the theoretical results for the conductivity 109 with the experimental data for σ 1 and σ 2 at different temperatures 190 . The theoretical results are obtained using the same λ = 1.7 and ω sf = 20meV as in the fit to the photoemission data along zone diagonals.…”

Section: The Optical Conductivitymentioning

confidence: 99%

A Spin Fluctuation Model for d-Wave Superconductivity

Chubukov¹,

Pines²,

Schmalian³

2003

The Physics of Superconductors

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We review the results of the spin-fermion model for correlated electron materials that are sufficiently close to an antiferromagnatic instability that their staggered static magnetic susceptibility in the normal state is large compared to that found in a conventional Fermi liquid. We demonstrate that for such materials magnetically-mediated superconductivity, brought about by the exchange of spin fluctuations, is a viable alternative to conventional phonon-mediated pairing, and leads to pairing in the d x 2 −y 2 channel. If the dominant interaction between quasiparticles is of electronic origin and, at energies much smaller than the fermionic bandwidth, can be viewed as being due to the emission and absorption of a collective, soft spin degree of freedom, the low-energy physics of these materials is accurately described by the spin-fermion model. The derived dynamic magnetic susceptibility and quasiparticle interaction coincide with the the phenomenonological forms used to fit NMR experiments and in earlier Eliashberg calculations. In discussing normal state properties, the pairing instability and superconducting properties, we focus our attention on those materials that, like the cuprate, organic, and some heavy electron superconductors, display quasi-two dimensional behavior. In the absence of superconductivity, at sufficiently low temperatures and energies, a nearly antiferromagnetic Fermi liquid is unconventional, in that the characteristic energy above which a Landau Fermi liquid description is no longer valid is not the Fermi energy, but is the much smaller spin-fluctuation energy,ω sf . For energies (or temperatures) between ω sf and the Fermi energy, the system behavior is quite different from that in a conventional Fermi liquid. Importantly, it is universal in that it is governed by just two input parameters -an effective spin-fermion interaction energy that sets the overall energy scale, and a dimensionless spin-fermion coupling constant that diverges at the antiferromagnetic quantum critical point. We discuss the pairing instability cased by the spin-fluctuation exchange, and "fingerprints" of a spin mediated pairing that are chiefly associated with the emergence of the resonance peak in the spin response of a d-wave superconductor. We identify these fingerprints in spectroscopic experiments on cuprateb superconconductors. We conclude with a discussion of open questions associated primarily with the nature of the pseudogap state found in underdoped cuprates.

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Optical studies of charge dynamics in optimally dopedBi2Sr2CaCu

Cited by 67 publications

References 26 publications

Terahertz magnetotransport measurements in underdopedPr2−xCexCuO4and comparison with angle-resolved phot

Terahertz magnetotransport measurements in underdopedPr2−xCexCuO4and comparison with angle-resolved phot

Interpretation of in-plane infrared response of high-Tccuprate superconductors involving spin fluctuations using quasiparticle spectral functions

A Spin Fluctuation Model for d-Wave Superconductivity

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