Fano effect in the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>a</mml:mi><mml:mo>−</mml:mo><mml:mi>b</mml:mi></mml:math>plane of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Nd</mml:mi></mml:mrow><mml:mrow><mml:mn>1.96</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Ce</mml:mi></mml:mrow><mml:mrow><mml:mn>0.04</mml:mn></mml:mrow></mm

Lupi, S.; Capizzi, M.; Calvani, P.; Ruzicka, Barbara; Maselli, P.; Dore, P.; Paolone, A.

doi:10.1103/physrevb.57.1248

Cited by 45 publications

(30 citation statements)

References 25 publications

(29 reference statements)

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“…The infrared optical absorption of perovskite-type materials, in particular, of copper oxide based high-T c superconductors and of the manganites has been the subject of intensive investigations [3][4][5][6][7][8][9][10][11][12]. Insulating SrTiO 3 has a perovskite structure and manifests a metal-insulator transition at room temperature around a doping of 0.002% La or Nb per unit cell [13].…”

Section: Introductionmentioning

confidence: 99%

Many-body large polaron optical conductivity inSrTi1−xNbxO3

et al. 2010

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Recent experimental data on the optical conductivity of niobium doped SrTiO3 are interpreted in terms of a gas of large polarons with effective coupling constant α ef f ≈ 2. The theoretical approach takes into account many-body effects, the electron-phonon interaction with multiple LOphonon branches, and the degeneracy and the anisotropy of the Ti t2g conduction band. Based on the Fröhlich interaction, the many-body large-polaron theory provides an interpretation for the essential characteristics, except -interestingly -for the unexpectedly large intensity of a peak at ∼ 130 meV, of the observed optical conductivity spectra of SrTi1−xNbxO3 without any adjustment of material parameters.

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Section: Introductionmentioning

confidence: 99%

Many-body large polaron optical conductivity inSrTi1−xNbxO3

et al. 2010

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“…Moreover, electronic and lattice fingerprints of 1D transport have not been systematically explored as a function of doping. The goal of this work is to apply infrared spectroscopy for the purpose of a detailed examination of spin/charge ordering effects in a series of well characterized LSCO crystals.Infrared spectroscopy is a mature and powerful technique for the study of phonons[9, 10] electron-lattice coupling [11,12] anharmonicity, [13] and charge and spin ordered states [6] resulting from a lowering of electronic and magnetic symmetry. Since precise measurements can be carried out with miniature single crystals, IR spectroscopy further permits a survey of the electronic anisotropy, which is naturally expected due the formation of stripes in cuprates.…”

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confidence: 99%

“…Infrared spectroscopy is a mature and powerful technique for the study of phonons[9, 10] electron-lattice coupling [11,12] anharmonicity, [13] and charge and spin ordered states [6] resulting from a lowering of electronic and magnetic symmetry. Since precise measurements can be carried out with miniature single crystals, IR spectroscopy further permits a survey of the electronic anisotropy, which is naturally expected due the formation of stripes in cuprates.…”

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confidence: 99%

Infrared signatures of hole and spin stripes inLa2−xSrxCuO4

et al. 2005

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We investigate the hole and lattice dynamics in a prototypical high temperature superconducting system La2−xSrxCuO4 using infrared spectroscopy. By exploring the anisotropy in the electronic response of CuO2 planes we show that our results support the notion of stripes. Nevertheless, charge ordering effects are not apparent in the phonon spectra. All crystals show only the expected infrared active modes for orthorhombic phases without evidence for additional peaks that may be indicative of static charge ordering. Strong electron-phonon interaction manifests itself through the Fano lineshape of several phonon modes. This analysis reveals anisotropic electron-phonon coupling across the phase diagram, including superconducting crystals. Due to the ubiquity of the CuO2 plane, these results may have implications for other high Tc superconductors.The nature of spin and/or charge stripes in the cuprates and their involvement to high temperature superconductivity are currently at the center of a debate in condensed matter physics.[1] The expression "stripes" is a general term indicating that spins and/or holes may arrange themselves in quasi-one dimensional, or more complicated self-organized patterns. The stripe-ordered state minimizes the energy of holes doped in an antiferromagnetic matrix thus leading to new inhomogeneous state of matter.[2] Static one-dimensional (1D) charge stripes have been observed in the La 2−x−y Nd y Sr x CuO 4 (LNSCO) system[3] with complimentary evidence from neutron and x-ray diffraction techniques. Although signatures of stripes by way of charge ordering have not been observed in La 2−x Sr x CuO 4 (LSCO) and other high temperature superconductors, there is evidence of the possible existence of dynamical stripes in these systems. [4] On the other hand, spin stripes have been discovered in LSCO[5] and many researchers agree upon their universality in high-T c superconductors. However a key issue regarding this new electronic state of matter concerns the role of stripes in relation to superconductivity, i.e. whether they are responsible for high temperature superconductivity or a competing phase with it.Signatures of quasi one dimensional behavior should be observable in optical spectroscopy. In particular the lowering of symmetry due the formation of rigid charge density waves results is known to have dramatic implications for infrared (IR) active phonons.[6] Electronic 1D behavior can be directly probed by way of frequency dependent conductivity. An observation of the anisotropic conductivity in weakly doped LSCO is consistent with the notion of stripes [7,8]. Notably these observations imply deviations from a hypothetical model in which the stripes are rigid rivers of charge embedded within an antiferromagnetic background. Moreover, electronic and lattice fingerprints of 1D transport have not been systematically explored as a function of doping. The goal of this work is to apply infrared spectroscopy for the purpose of a detailed examination of spin/charge ordering effects in a series of ...

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“…Below 320 K, for E ⊥ c the broad contribution at 530 cm −1 splits into two components separated by about 40 cm −1 ; for E c all lines shift abruptly to higher frequencies and new components do appear. Incidentally, no phonon line displays Fano-like asymmetries, [23] thus confirming the absence of a free-carrier background in the phonon energy range.…”

Section: Atoms Wyckoffmentioning

confidence: 54%

Infrared study of the charge-ordered multiferroicLuFe2O4

et al. 2010

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The reflectivity of a large LuFe2O4 single crystal has been measured with the radiation field either perpendicular or parallel to the c axis of its rhombohedral structure, from 10 to 500K, and from 7 to 16000 cm −1 . The transition between the two-dimensional and the three-dimensional charge order at TCO = 320 K is found to change dramatically the phonon spectrum in both polarizations. The number of the observed modes above and below TCO, according to a factor-group analysis, is in good agreement with a transition from the rhombohedral space group R3m to the monoclinic C2/m. In the sub-THz region a peak becomes evident at low temperature, whose origin is discussed in relation with previous experiments.

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Fano effect in thea−bplane ofNd1.96Ce0.04

Cited by 45 publications

References 25 publications

Many-body large polaron optical conductivity inSrTi1−xNbxO3

Many-body large polaron optical conductivity inSrTi1−xNbxO3

Infrared signatures of hole and spin stripes inLa2−xSrxCuO4

Infrared study of the charge-ordered multiferroicLuFe2O4

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