Plane-polarized Raman continuum in the insulating and superconducting layered cuprates

Reznik, D.; Cooper, S. L.; Klein, Miles V.; Lee, W. C.; Ginsberg, D. M.; Максимов, А. А.; Puchkov, A. V.; Tartakovskii, I. I.; Cheong, Sang‐Wook

doi:10.1103/physrevb.48.7624

Cited by 62 publications

(43 citation statements)

References 25 publications

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“…The main discrepancy is their spectral shape above 2000-4000 cm −1 . In contrast to our results and those by Sulewski and coworkers 36 and Reznik et al 20 the spectra shown in Fig. 9 (b) of Ref.…”

contrasting

confidence: 99%

“…Up to 4000 cm −1 , the data agree well with those on Gd 2 CuO 4 36 . Similarly, qualitative agreement is also found with results on other cuprates 20,38,39,41 . The structures at low temperature between 1000 and 2000 cm −1 are due to twophonon processes 42 which are observed only in the un-doped compound and become weaker at high temperature [ Fig.…”

Section: Response At High Energiessupporting

confidence: 88%

“…7 we plot the Raman response Rχ ′′ µ (Ω, T ) for two temperatures at all four symmetries of the tetragonal point group D 4h which is by and large applicable for the high-energy part of the spectra. Similar results have been published for Gd 2 CuO 4 at room temperature 36 and, for a smaller set of polarizations, for various other cuprates 20,[37][38][39][40][41] . Due to the orthorhombic distortion below about 500 K, a small a − b anisotropy is also found at high energies -in addition to a strong one in the energy range where phonons occur 41 .…”

Section: Response At High Energiessupporting

confidence: 85%

“…The scattered light was analyzed in most of the cases with a subtractively coupled Jarrell-Ash 25-100 scanning spectrometer. The image of the laser focus on the entrance slit was smaller than the slit width at all energy shifts, as verified with a CCD (charge coupled device) camera (see also 20 ), to avoid losses due to the chromatic aberration of the collection optics.…”

Section: B Raman Experimentsmentioning

confidence: 88%

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Electron interactions and charge ordering in CuO 2 compounds

Muschler

Prestel

Tassini

et al. 2010

Eur. Phys. J. Spec. Top.

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We present results of inelastic light scattering experiments on singlecrystalline La2−xSrxCuO4 in the doping range 0.00 ≤ x = p ≤ 0.30 and Tl2Ba2CuO 6+δ at p = 0.20 and p = 0.24. The main emphasis is placed on the response of electronic excitations in the antiferromagnetic phase, in the pseudogap range, in the superconducting state, and in the essentially normal metallic state at x ≥ 0.26, where no superconductivity could be observed. In most of the cases we compare B1g and B2g spectra which project out electronic properties close to (π, 0) and (π/2, π/2), respectively. In the channel of electron-hole excitations we find universal behavior in B2g symmetry as long as the material exhibits superconductivity at low temperature. In contrast, there is a strong doping dependence in B1g symmetry: (i) In the doping range 0.20 ≤ p ≤ 0.25 we observe rapid changes of shape and temperature dependence of the spectra. (ii) In La2−xSrxCuO4 new structures appear for x < 0.13 which are superposed on the electron-hole continuum. The temperature dependence as well as model calculations support an interpretation in terms of charge-ordering fluctuations. For x ≤ 0.05 the response from fluctuations disappears at B1g and appears at B2g symmetry in full agreement with the orientation change of stripes found by neutron scattering. While, with a grain of salt, the particle-hole continuum is universal for all cuprates the response from fluctuating charge order in the range 0.05 ≤ p < 0.16 is so far found only in La2−xSrxCuO4. We conclude that La2−xSrxCuO4 is close to static charge order and, for this reason, may have a suppressed Tc.

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contrasting

confidence: 99%

Section: Response At High Energiessupporting

confidence: 88%

Section: Response At High Energiessupporting

confidence: 85%

Section: B Raman Experimentsmentioning

confidence: 88%

See 2 more Smart Citations

Electron interactions and charge ordering in CuO 2 compounds

Muschler

Prestel

Tassini

et al. 2010

Eur. Phys. J. Spec. Top.

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“…9 . At the lower doping the low-frequency Raman B 1g intensity is suppressed as the temperature decreases, whereas at the higher doping the initial slope is seen to increase as the temperature decreases again consistent with data [34][35][36][37] and with exact diagonalization of small clusters in the t − J model [38].…”

Section: Fig 1: Ramansupporting

confidence: 82%

Two-Particle Response in Cluster Dynamical Mean-Field Theory: Formalism and Application to the Raman Response of High-Temperature Superconductors

2012

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A method is presented for the unbiased numerical computation of two-particle response functions of correlated electron materials via a solution of the dynamical mean-field equations in the presence of a perturbing field. The power of the method is demonstrated via a computation of the Raman B1g and B2g scattering intensities of the two dimensional Hubbard model, in parameter regimes believed to be relevant to high-temperature superconductivity. The theory reproduces the 'twomagnon' peak characteristic of the Raman intensity of the insulating parent compounds of high-Tc copper oxide superconductors and shows how it evolves to a quasiparticle response as carriers are added. The method can be applied in any situation where a solution of the equilibrium dynamical mean-field equations is feasible. [3,4], has transformed our understanding of correlated electron physics. In the particular case of the two-dimensional Hubbard model, believed [5] to represent the physics of high temperature superconductors, the method has provided new insights into the correlation-driven ('Mott') metal-insulator transition [6,7], the pseudogap regime that separates the Mott insulator from the Fermi liquid metal [7][8][9][10] In this paper we present a new method for determining the two-particle response in cluster dynamical mean-field theory and demonstrate its effectiveness via a computation of the doping dependence of the Raman scattering amplitude of the two-dimensional Hubbard model from the Mott insulating to the Fermi liquid regime. Raman spectroscopy has been of fundamental importance to high temperature superconductivity [24] but the theoretical description in terms of an underlying Hubbard model involves vertex corrections in an essential way and has not been systematically studied.To introduce our method we recall salient features of the theory of linear response [25], defined quantum mechanically as the leading-order difference of the expectation value of an operatorR in the presence and absence of a probe field P . This is given by R P = Tr R G P − Tr R G eq = χ RP P + O(P 2 ) with(1) Here G eq = (G −1 0 − Σ eq ) −1 is the equilibrium (P = 0) Green function, related in the standard way to a bare Green function G 0 and a self energy Σ. We have omitted a possible term arising from explicit dependence of R on P ; this gives rise to the 'diamagnetic' term in the optical conductivity but is not otherwise relevant. The first term in Eq. 1 gives the 'bubble term', computable from knowledge of the one-electron Green function and the bare vertex δG −1 0 /δP ; the second term, arising from changes in the many-body physics due to the perturbation, is the vertex correction of interest here.For wide classes of strongly correlated materials, neither perturbative diagrammatic expansions about a mean-field solution nor partial (e.g RPA or GW) resummations suffice; a fully nonperturbative treatment is required. For the one electron Green function, cluster dynamical mean-field theory [2] provides such a treatment. In this theory the electron ...

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Electronic Raman scattering and phonon self-energy effects in theR-123 system: Signatures of gap and pseudogap

Böck

1999

Ann. Phys.

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Using Raman spectroscopy and transport measurements we investigate thin epitaxial films of Y 1Àx (Pr, Ca) x Ba 2 Cu 3 O 6y . We explore the electronic Raman responses in A 1g , B 1g , and B 2g symmetry obtained after subtraction of phononic excitations, and especially, the 2D peaks that form out of the electronic background below T c . We find that the energy of the B 1g 2D peak, which is a measure of the gap value, increases monotonically with decreasing doping until the peak becomes unresolvable. In contrast, the peak in A 1g symmetry follows T c being still resolvable in the Pr-doped films. The B 2g response is weak and a 2D peak is only detected at the highest doping level. As a consequence of strong electron-phonon coupling, the B 1g phonon at $340 cm À1 exhibits a pronounced Fano-type line shape. We use a phenomenological model to describe the line shape that takes into account real and imaginary part of the electronic response. It allows us to obtain the self-energy corrections and the mass-enhancement factor l as a measure of the coupling. In the normal state we find l 0X015 around optimal doping and decreasing values with decreasing doping. The electron-phonon coupling increases strongly below T c in overdoped samples in which the B 1g 2D peaks appear in the vicinity of the phonon. Self-energy effects observed in the superconducting state can only partly be assigned to the redistributing electronic response. Anomalies with respect to frequency, linewidth, and intensity remain. They appear at increasing temperatures with decreasing doping and we provide evidence that they are connected to the presence of the pseudogap. We supplement our study by a comparison with single crystal data and investigate the influence of site-substitutional disorder on the electronic response and the electronphonon interaction.Since the discovery of the cuprate high-temperature superconductors (HTS) [1] it has been established that the important common feature of all cuprates are the copper-oxygen (CuO 2 ) planes. Even though not discovered yet, it is believed that the mechanism causing the high transition temperatures T c is located in and related to these planes. Often discussed candidates for the pairing mechanism are an exchange of antiferromagnetic fluctuations [2Ð3] or interlayer tunneling [4,5]. The role phonons play in the mechanism is not resolved [6Ð8]. Isotope experiments indicate that phonons may be involved [9], at least away from optimal doping which is near $ 0X16 holes per plane in the unit cell.

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Plane-polarized Raman continuum in the insulating and superconducting layered cuprates

Cited by 62 publications

References 25 publications

Electron interactions and charge ordering in CuO 2 compounds

Electron interactions and charge ordering in CuO 2 compounds

Two-Particle Response in Cluster Dynamical Mean-Field Theory: Formalism and Application to the Raman Response of High-Temperature Superconductors

Electronic Raman scattering and phonon self-energy effects in theR-123 system: Signatures of gap and pseudogap

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