34 research outputs found
Thermodynamic phase diagram of the competition between superconductivity and charge order in cuprates
We argue that there is a special doping point in the phase diagram of
cuprates, such that the condensation of holes into a charge-ordered and into a
superconducting phase are degenerate in energy but with an energy barrier in
between. We present a Monte Carlo simulation of this problem without and with
quenched disorder. While in the clean case charge order and superconductivity
are separated by a first-order line which is nearly independent of temperature,
in the presence of quenched disorder, charge order is fragmented into domains
separated by superconducting filaments reminiscent of the supersolid behavior
in He. The resulting phase diagram is in good agreement with the
experiments.Comment: 30 pages, 17 figure
Aspectos fundamentales de la suspensión de pagos
La presente tesis está compuesta por ocho capítulos enfocados en dar una visión doctrinaria y jurídica de la institución de la suspensión de pagos, para lo cual y en cuanto al aspecto doctrinario se hizo acopio de varios tratadistas, en donde la bibliografía más precisa y abundante es de autores españoles y mexicanos, mientras que para él aspectos jurídico se utilizó la siguiente legislación salvadoreña: el Código de Comercio, la Ley de Procedimientos Mercantiles en cuanto a su tramitación procesal, así como también el Código de Procedimientos Civiles
Generalized Rashba Electron-Phonon Coupling and Superconductivity in Strontium Titanate
SrTiO3 is known for its proximity to a ferroelectric phase and for showing an
'optimal' doping for superconductivity with a characteristic dome-like
behaviour resembling systems close to a quantum critical point. Several
mechanisms have been proposed to link these phenomena, but the abundance of
undetermined parameters prevents a definite assessment. Here, we use ab initio
computations supplemented with a microscopic model to study the linear coupling
between conduction electrons and the ferroelectric soft transverse modes
allowed in the presence of spin-orbit coupling. We find a robust Rashba-like
coupling, which can become surprisingly strong for particular forms of the
polar eigenvector. We characterize this sensitivity for general eigenvectors
and, for the particular form deduced by hyper-Raman scattering experiments, we
find a BCS pairing coupling constant of the right order of magnitude to support
superconductivity. The ab initio computations enable us to go beyond the
linear-in-momentum conventional Rashba-like interaction and naturally explain
the dome behaviour including a characteristic asymmetry. The dome is attributed
to a momentum dependent quenching of the angular momentum due to a competition
between spin-orbit and hopping energies. The optimum density for having maximum
Tc results in rather good agreement with experiments without free parameters.
These results make the generalized Rashba dynamic coupling to the ferroelectric
soft mode a compelling pairing mechanism to understand bulk superconductivity
in doped SrTiO3.Comment: 18 pages, 8 figure
Enhanced Critical Field of Superconductivity at an Oxide Interface
The nature of superconductivity and its interplay with strong spin-orbit
coupling at the KTaO3(111) interfaces remains a subject of debate. To address
this problem, we grew epitaxial LaMnO3/KTaO3(111) heterostructures. We show
that superconductivity is robust against the in-plane magnetic field, with the
critical field of superconductivity reaching 25 T in optimally doped
heterostructures. The superconducting order parameter is highly sensitive to
carrier density. We argue that spin-orbit coupling drives the formation of
anomalous quasiparticles with vanishing magnetic moment, providing the
condensate significant immunity against magnetic fields beyond the Pauli
paramagnetic limit. These results offer design opportunities for
superconductors with extreme resilience against magnetic field
Assessment of pavement deflection under vehicle loads using a 3D-DIC system in the field
This study aims to introduce the use of 3D-digital image correlation (DIC) to the in situ testing of pavements and to support the development of techniques for a rapid evaluation of the conservation status of existing roads. Little research was found on this topic. The passage of a car wheel on an asphalt pavement was adopted as a case study. The DIC measurements were compared to those gathered by contact sensors. From a qualitative point of view, the DIC measurements captured the realistic shape of a deflection basin. From a quantitative point of view, the deflection values provided by the DIC system had a mean error of 0.015 mm and a standard deviation of 0.011 mm. At the moment of highest load, these errors had a mean value and standard deviation of − 0.016 mm and 0.021 mm, respectively. Thus, to improve the accuracy of the system, we propose modifying the camera support, speckle pattern, and control of natural lightWe thank Extraco S.A. for allowing us to perform the test on their company facilities. This work was supported by the Strategic Researcher Cluster BioReDes funded by the Xunta de Galicia (Regional Government of Galicia) under project ref. ED431E 2018/09 and by the Xunta de Galicia under the grant “Financial aid for the consolidation and structure of competitive units of investigation in the universities of the University Galician System (2020-22)” under project ref. ED341B 2016/30. This work was also made possible due to the Spanish Agencia Estatal de Investigación (AEI), since Dr. Bastos was contracted in the frame of the postdoctoral grant Juan de la Cierva – Formación (FJC2019-039743-I/AEI/10.13039/501100011033)S