| 1. |
- Aad, G., et al.
(författare)
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- 2012
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Ingår i: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368 .- 1550-7998. ; 86:7
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Tidskriftsartikel (refereegranskat)
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| 2. |
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| 3. |
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| 4. |
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| 5. |
- Arpaia, Riccardo, 1985, et al.
(författare)
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Dynamical charge density fluctuations pervading the phase diagram of a Cu-based high-Tc superconductor
- 2019
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 365:6456, s. 906-910
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Tidskriftsartikel (refereegranskat)abstract
- Charge density modulations have been observed in all families of high–critical temperature (Tc) superconducting cuprates. Although they are consistently found in the underdoped region of the phase diagram and at relatively low temperatures, it is still unclear to what extent they influence the unusual properties of these systems. Using resonant x-ray scattering, we carefully determined the temperature dependence of charge density modulations in YBa2Cu3O7–d and Nd1+xBa2–xCu3O7–d for several doping levels. We isolated short-range dynamical charge density fluctuations in addition to the previously known quasi-critical charge density waves. They persist up to well above the pseudogap temperature T*, are characterized by energies of a few milli–electron volts, and pervade a large area of the phase diagram.
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| 6. |
- Arpaia, Riccardo, 1985, et al.
(författare)
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Signature of quantum criticality in cuprates by charge density fluctuations
- 2023
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Ingår i: Nature Communications. - 2041-1723 .- 2041-1723. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- The universality of the strange metal phase in many quantum materials is often attributed to the presence of a quantum critical point (QCP), a zero-temperature phase transition ruled by quantum fluctuations. In cuprates, where superconductivity hinders direct QCP observation, indirect evidence comes from the identification of fluctuations compatible with the strange metal phase. Here we show that the recently discovered charge density fluctuations (CDF) possess the right properties to be associated to a quantum phase transition. Using resonant x-ray scattering, we studied the CDF in two families of cuprate superconductors across a wide doping range (up to p = 0.22). At p* ≈ 0.19, the putative QCP, the CDF intensity peaks, and the characteristic energy Δ is minimum, marking a wedge-shaped region in the phase diagram indicative of a quantum critical behavior, albeit with anomalies. These findings strengthen the role of charge order in explaining strange metal phenomenology and provide insights into high-temperature superconductivity.
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| 7. |
- De Angelis, M., et al.
(författare)
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Evaluation of the internal field in lithium niobate ferroelectric domains by an interferometric method
- 2004
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Ingår i: Applied physics letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 85:4, s. 2785-
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Tidskriftsartikel (refereegranskat)abstract
- We report on the evaluation of internal electric field of a ferroelectric engineered-domain in a LiNbO3 wafer crystal by detecting optical path length variation with a noninvasive interferometric inspection method. The lithium niobate wafer has been patterned and subjected to electric field poling to obtain two antiparallel ferroelectric domains separated by a single domain wall. The crystal has been mounted into one arm of a Mach-Zehnder-type interferometer to study the phase map and evaluate the effects of domain reversion by a digital holographic technique. Evaluation of the internal field and consequent variation of the electro-optical properties of the different domains is analyzed.
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| 8. |
- Ferraro, P., et al.
(författare)
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Surface topography of microstructures in lithium niobate by digital holographic microscopy
- 2004
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Ingår i: Measument science and technology15. - : IOP Publishing. - 0957-0233 .- 1361-6501. ; 15:5, s. 961-
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Tidskriftsartikel (refereegranskat)abstract
- We report here on the application of digital holographic microscopy as a metrological tool for the inspection and the micro-topography reconstruction of different microstructures fabricated in bulk lithium niobate by differential etching of reversed ferroelectric domain patterned crystals. These structures have a range of applications in optical ridge waveguides, alignment structures, V-grooves, micro-tips and micro-cantilever beams and precise control of the surface quality and topography is required. The technique allows us to obtain digitally a high-fidelity surface topography description of the specimen with only one image acquisition allowing us to have relatively simple and compact set-ups able to give quantitative information on object morphology. The advantages of this technique compared to traditional microscopy are discussed.
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| 9. |
- Grilli, Simonetta, et al.
(författare)
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Two-dimensional mapping of electro-optic phase retardation in lithium niobate crystals by digital holography
- 2005
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Ingår i: Optics letters. - 0146-9592. ; 30:13, s. 1671-1673
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate accurate two-dimensional mapping of the phase retardation induced by the electro-optic effect in lithium niobate crystals. Off-axis digital holography is used to investigate congruent z-cut crystals. The spatially resolved optical path difference is interferometrically measured while a linearly rising voltage ramp is applied to the crystal. This procedure provides information on the uniformity of crystals' electro-optic properties and offers the ability to detect the presence of defects that is of fundamental importance for reliable processing of photonic devices.
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| 10. |
- Paturzo, M., et al.
(författare)
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Investigation of electric internal field in congruent LiNbO3 by electro-optic effect
- 2004
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Ingår i: Applied physics letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 85, s. 5652-5654
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the effect of the defect-induced internal field on the electro-optic behavior of z-cut congruent lithium niobate crystals. We measure, by a spatially resolved interferometric technique, the phase retardation due to an external applied voltage occurring in two regions with opposite ferroelectric polarization. When measurements are performed just after electrical poling, the two opposite domains show a different electro-optic behavior. We interpret this as due to an elastic component of the internal field. In fact, the asymmetric behavior disappears when the sample is thermally annealed, i.e., when the internal field vanishes
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