A5007999650- Physics of Superconductivity and Magnetism
- Electronic and Structural Properties of Oxides
- Magnetic and transport properties of perovskites and related materials
- Quantum and electron transport phenomena
- Advanced Condensed Matter Physics
- Magnetic properties of thin films
- Semiconductor materials and devices
- Theoretical and Computational Physics
- Surface and Thin Film Phenomena
- Iron-based superconductors research
- Superconducting Materials and Applications
- Superconducting and THz Device Technology
- Rare-earth and actinide compounds
- Advanced Electrical Measurement Techniques
- Semiconductor Quantum Structures and Devices
- Atomic and Subatomic Physics Research
- Terahertz technology and applications
- Cold Atom Physics and Bose-Einstein Condensates
- Particle Detector Development and Performance
- Transition Metal Oxide Nanomaterials
- Diamond and Carbon-based Materials Research
- Advanced Materials Characterization Techniques
- Quantum, superfluid, helium dynamics
- Particle physics theoretical and experimental studies
- Particle accelerators and beam dynamics
Centre National de la Recherche Scientifique
2015-2025
ESPCI Paris
2016-2025
Laboratoire de Physique et d’Étude des Matériaux
2016-2025
Sorbonne Université
2015-2025
Université Paris Sciences et Lettres
2016-2025
Université Sorbonne Nouvelle
2023
École nationale des ponts et chaussées
2023
Sorbonne University Abu Dhabi
2023
Institute of Electrical and Electronics Engineers
2020
University of Catania
2020
We investigate Josephson coupling through a ferromagnetic thin film using superconductor-insulator-ferromagnet-superconductor planar junctions. Damped oscillations of the critical current are observed as function layer thickness. show that they result from exchange energy gained or lost by quasiparticle Andreev-reflected at ferromagnet-superconductor interface. The cancels out transition positive ("0") to negative ("pi") coupling, in agreement with theoretical calculations.
Planar tunneling spectroscopy reveals damped oscillations of the superconducting order parameter induced into a ferromagnetic thin film by proximity effect. The are due to finite momentum transfer provided for Cooper pairs splitting spin-up and spin-down bands in ferromagnet. As consequence, negative values spectra capsized ("pi state"). oscillations' damping period set same length scale, which depends on spin polarization.
In this Letter, we show that a superconducting two-dimensional electron gas is formed at the LaTiO3/SrTiO3 interface whose transition temperature can be modulated by back-gate voltage. The consists of two types carriers: majority low-mobility carriers always present, and few high-mobility ones injected electrostatic doping. calculation spatial distribution in confinement potential shows electrons responsible for superconductivity set edge extension tuned field effect.
Abstract The discovery of two-dimensional electron gases (2DEGs) at oxide interfaces—involving electrons in narrow d -bands—has broken new ground, enabling the access to correlated states that are unreachable conventional semiconductors based on s - and p electrons. There is a growing consensus emerging properties these novel quantum wells—such as 2D superconductivity magnetism—are intimately connected specific orbital symmetries 2DEG sub-band structure. Here we show crystal orientation...
Abstract The recent development in the fabrication of artificial oxide heterostructures opens new avenues field quantum materials by enabling manipulation charge, spin and orbital degrees freedom. In this context, discovery two-dimensional electron gases (2-DEGs) at LaAlO 3 /SrTiO interfaces, which exhibit both superconductivity strong Rashba spin-orbit coupling (SOC), represents a major breakthrough. Here, we report on realisation field-effect device, whose physical properties, including...
Abstract In LaTiO 3 /SrTiO and LaAlO heterostructures, the bending of SrTiO conduction band at interface forms a quantum well that contains superconducting two-dimensional electron gas (2-DEG). Its carrier density electronic properties, such as superconductivity Rashba spin-orbit coupling can be controlled by electrostatic gating. this article we show Fermi energy lies intrinsically near top well. Beyond filling threshold, electrons added gating escape from well, hence limiting possibility...
In this paper we investigate the effect of disorder on highly correlated electron systems, which exhibit metal-insulator transition (MIT) and structural-phase (SPT). We show that ion irradiation is strikingly different between ${\mathrm{V}}_{2}{\mathrm{O}}_{3}$ $\mathrm{V}{\mathrm{O}}_{2}$, two otherwise similar materials. Upon irradiation, MIT SPT temperatures in decrease drastically at low absolute dosages, much lower than for $\mathrm{V}{\mathrm{O}}_{2}$. At a threshold dose, insulating...
Oxide heterostructures are of great interest both for fundamental and applicative reasons. In particular the two-dimensional electron gas at LaAlO$_3$/SrTiO$_3$ or LaTiO$_3$/SrTiO$_3$ interfaces displays many different physical properties functionalities. However there clear indications that interface electronic state is strongly inhomogeneous therefore it crucially relevant to investigate possible intrinsic mechanisms underlying this inhomogeneity. Here electrostatic potential confining...
After almost twenty years of intense work on the celebrated LaAlO3/SrTiO3system, recent discovery a superconducting two-dimensional electron gas (2-DEG) in (111)-oriented KTaO3-based heterostructures injects new momentum to field oxides interface. However, while both interfaces share common properties, experiments also suggest important differences between two systems. Here, we report gate tunable superconductivity 2-DEGs generated at surface KTaO3 crystal by simple sputtering thin Al layer....
The two-dimensional electron gas at the LaTiO${}_{3}$/SrTiO${}_{3}$ or LaAlO${}_{3}$/SrTiO${}_{3}$ oxide interfaces becomes superconducting when carrier density is tuned by gating. measured resistance and superfluid reveal an inhomogeneous superconductivity resulting from percolation of filamentary structures ``puddles'' with randomly distributed critical temperatures, embedded in a nonsuperconducting matrix. Following evidence that related to appearance high-mobility carriers, we model...
A study of magnetic-field tuned superconductor-insulator transitions in amorphous $Nb_{0.15}Si_{0.85}$ thin films shows that quantum are characterized by an unambiguous signature -- a kink the temperature profile critical magnetic field. Using this criterion, we show nature transition depends on orientation field with respect to film. For perpendicular field, is controlled fluctuations indications for existence Bose insulator; while parallel classical, driven breaking Cooper pairs at...
We have developed a masked ion irradiation technique to engineer the energy landscape for vortices in oxide superconductors. This approach associates possibility design geometry at nanoscale with unique capability adjust depth of wells vortices. enabled us unveil key role vortex channeling modulating amplitude field matching effects artificial landscape, and make latter govern flux dynamics over an unusually wide range temperatures applied fields high-temperature superconducting films.
We report on an experimental and theoretical study of the high-frequency mixing properties ion-irradiated YBa2Cu3O7 Josephson junctions embedded in THz antennas. investigated influence local oscillator power frequency device performances. The data are compared with predictions general three-port model for mixers which junction is described by resistively shunted model. A good agreement obtained conversion efficiency different ranges, spanning above below characteristic frequencies fc junctions.
The large diversity of exotic electronic phases displayed by two-dimensional superconductors confronts physicists with new challenges. These include the recently discovered quantum Griffith singularity in atomic Ga films, topological proximized insulators and unconventional Ising pairing transition metal dichalcogenide layers. In LaAlO3/SrTiO3 heterostructures, a gate tunable superconducting electron gas is confined well at interface between two insulating oxides. Remarkably, coexists both...
One of the hallmarks Berezinskii-Kosterlitz-Thouless (BKT) transition in two-dimensional (2D) superconductors is universal jump superfluid density, that can be indirectly probed via non-linear exponent current-voltage $IV$ characteristics. Here, we compare experimental measurements characteristics two cases, namely NbN thin films and SrTiO$_3$-based interfaces. While former display a paradigmatic example BKT-like effects, latter do not seem to justify BKT analysis. Rather, observed well...
Abstract The term tunnel electroresistance (TER) denotes a fast, non-volatile, reversible resistance switching triggered by voltage pulses in ferroelectric junctions. It is explained subtle mechanisms connected to the voltage-induced reversal of polarization. Here we demonstrate that effects functionally indistinguishable from TER can be produced simpler junction scheme—a direct contact between metal and an oxide—through different mechanism: redox reaction modifies oxide’s ground-state. This...
Reproducible high-Tc Josephson junctions have been made in a rather simple two-step process using ion irradiation. A microbridge (1 to 5μm wide) is firstly designed by irradiating c-axis-oriented YBa2Cu3O7−δ film through gold mask such as the nonprotected part becomes insulating. lower Tc then defined within bridge with much fluence narrow slit (20 nm) opened standard electronic photoresist. These planar junctions, whose settings can be finely tuned, exhibit reproducible and nearly ideal...