417 research outputs found
Three-dimensional dispersion induced by extreme tensile strain in La_(2–x)Sr_xCuO_4 films
The electronic band structure probed by angle-resolved photoemission spectroscopy on thin epitaxial La2–xSrxCuO4 films under extreme tensile strain shows anomalous features compatible with c-axis dispersion. This result is in striking contrast with the usual quasi-two-dimensional (2D) dispersion observed up to now in most superconducting cuprates, including relaxed and compressively strained La2–xSrxCuO4 films grown under the same conditions. The data were analyzed using a 3D tight-binding dispersion for a body-centered-tetragonal lattice. We relate the enhancement of the c-axis dispersion to the significant displacement of the apical oxygen induced by epitaxial strain
Linear and nonlinear coupling of quantum dots in microcavities
We discuss the topical and fundamental problem of strong-coupling between a
quantum dot an the single mode of a microcavity. We report seminal quantitative
descriptions of experimental data, both in the linear and in the nonlinear
regimes, based on a theoretical model that includes pumping and quantum
statistics.Comment: Proceedings of the symposium Nanostructures: Physics and Technology
2010 (http://www.ioffe.ru/NANO2010), 2 pages in proceedings styl
Growth-induced electron mobility enhancement at the LaAlO/SrTiO interface
We have studied the electronic properties of the 2D electron liquid present
at the LaAlO/SrTiO interface in series of samples prepared at different
growth temperatures. We observe that interfaces fabricated at 650{\deg}C
exhibit the highest low temperature mobility () and the lowest sheet carrier density (). These samples show metallic behavior and
Shubnikov-de Haas oscillations in their magnetoresistance. Samples grown at
higher temperatures (800-900{\deg}C) display carrier densities in the range of
and mobilities of at 4K. Reducing their carrier density by field
effect to lowers their mobilites to
bringing the conductance to the
weak-localization regime
Tunable Rashba spin-orbit interaction at oxide interfaces
The quasi-two-dimensional electron gas found at the LaAlO3/SrTiO3 interface
offers exciting new functionalities, such as tunable superconductivity, and has
been proposed as a new nanoelectronics fabrication platform. Here we lay out a
new example of an electronic property arising from the interfacial breaking of
inversion symmetry, namely a large Rashba spin-orbit interaction, whose
magnitude can be modulated by the application of an external electric field. By
means of magnetotransport experiments we explore the evolution of the
spin-orbit coupling across the phase diagram of the system. We uncover a steep
rise in Rashba interaction occurring around the doping level where a quantum
critical point separates the insulating and superconducting ground states of
the system
Two-dimensional quantum oscillations of the conductance at LaAlO3/SrTiO3 interfaces
We report on a study of magnetotransport in LaAlO3/SrTiO3 interfaces
characterized by mobilities of the order of several thousands cm/Vs. We
observe Shubnikov-de Haas oscillations that indicate a two-dimensional
character of the Fermi surface. The frequency of the oscillations signals a
multiple sub-bands occupation in the quantum well or a multiple valley
configuration. From the temperature dependence of the oscillation amplitude we
extract an effective carrier mass \,. An electric field
applied in the back-gate geometry increases the mobility, the carrier density
and the oscillation frequency.Comment: 4 pages, 4 figure
Drag in a resonantly driven polariton fluid
We study the linear response of a coherently driven polariton fluid in the pump-only configuration scattering against a point-like defect and evaluate analytically the drag force exerted by the fluid on the defect. When the system is excited near the bottom of the lower polariton dispersion, the sign of the interaction-renormalised pump detuning classifies the collective excitation spectra into three different categories (Ciuti and Carusotto 2005 Phys. Status Solidi b 242 2224): linear for zero, diffusive-like for positive and gapped for negative detuning. We show that both cases of zero and positive detuning share a qualitatively similar crossover of the drag force from the subsonic to the supersonic regime as a function of the fluid velocity, with a critical velocity given by the speed of sound found for the linear regime. In contrast, for gapped spectra, we find that the critical velocity exceeds the speed of sound. In all cases, the residual drag force in the subcritical regime depends on the polariton lifetime only. Also, well below the critical velocity, the drag force varies linearly with the polariton lifetime, in agreement with previous work (Cancellieri et al 2010 Phys. Rev. B 82 224512), where the drag was determined numerically for a finite-size defect
The transbonchial lung biopsy for diagnosis of diffuse parenchymal lung disease; Pro
The diagnosis of diffuse parenchymal lung disease (DPLD) may require invasive procedures after all noninvasive tools have failed. The clinical context in which these diseases develop and the radiological patterns are crucial for defining the timing and the methods to be used. After the introduction in clinical practice of HRCT scan, the evaluation of imaging patterns, along with the immunological status of the patient and the clinical course of the disease (acute vs. chronic) seem to be crucial to choose the best diagnostic procedure
Nanodot-Cavity Electrodynamics and Photon Entanglement
Quantum electrodynamics of excitons in a cavity is shown to be relevant to
quantum operations. We present a theory of an integrable solid-state quantum
controlled-phase gate for generating entanglement of two photons using a
coupled nanodot-microcavity-fiber structure. A conditional phase shift of
is calculated to be the consequence of the giant optical
nonlinearity keyed by the excitons in the cavities. Structural design and
active control, such as electromagnetic induced transparency and pulse shaping,
optimize the quantum efficiency of the gate operation.Comment: 4 pages 3 figure
Adenocarcinoma classification: patterns and prognosis
Lung cancer is the most frequent human malignancy and the principal cause of cancer-related death worldwide. Adenocarcinoma is now the main histologic type, accounting for almost half of all the cases. The 2015 World Health Organization has adopted the classification recently developed by the International Association for the Study of Lung Cancer, American Thoracic Society, and European Respiratory Society. This new adenocarcinoma classification has incorporated up-to-date advances in radiological, molecular and oncological knowledge, providing univocal diagnostic criteria and terminology. For resection specimens, new entities have been defined such as adenocarcinoma in situ and minimally invasive adenocarcinoma to designate adenocarcinomas, mostly nonmucinous and ≤ 3 cm in size, with either pure lepidic growth or predominant lepidic growth with ≤ 5 mm invasion, respectively. For invasive adenocarcinoma, the new classification has introduced histological subtyping according to the predominant pattern of growth of the neoplastic cells: lepidic (formerly non mucinous brochioloalveolar adenocarcinoma), acinar, papillary, micropapillary, and solid. Of note, micropapillary pattern is a brand new histologic subtype. In addition, four variants of invasive adenocarcinoma are recognized, namely invasive mucinous (formerly mucinous brochioloalveolar adenocarcinoma), colloid, fetal, and enteric. Importantly, three variants that were considered in the previous classification have been eliminated, specifically mucinous cystadenocarcinoma, signet ring cell, and clear cell adenocarcinoma. This review presents the changes introduced by the current histological classification of lung adenocarcinoma and its prognostic implications
Effect of the Pauli Exclusion Principle in the Many-Electron Wigner Function
An analysis of the Wigner function for identical particles is presented. Four situations have been considered. i) A scattering process between two indistinguishable electrons described by a minimum uncertainty wave packets showing the exchange and correlation hole in Wigner phase space. ii) An equilibrium ensemble of N electrons in a one-dimensional box and in a one-dimensional harmonic potential showing that the reduced single particle Wigner function as a function of the energy defined in the Wigner phase-space tends to a Fermi distribution. iii) The reduced one-particle transport-equation for the Wigner function in the case of interacting electrons showing the need for the two-particle reduced Wigner function within the BBGKY hierarchy scheme. iv) The electron-phonon interaction in the two-particle case showing co-participation of two electrons in the interaction with the phonon bath
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