A5068474404- Physics of Superconductivity and Magnetism
- Quantum and electron transport phenomena
- Semiconductor Quantum Structures and Devices
- Advancements in Semiconductor Devices and Circuit Design
- Nanowire Synthesis and Applications
- Photonic and Optical Devices
- Surface and Thin Film Phenomena
- Cold Atom Physics and Bose-Einstein Condensates
- Silicon Nanostructures and Photoluminescence
- Superconducting and THz Device Technology
- Superconducting Materials and Applications
- Mechanical and Optical Resonators
- Semiconductor materials and devices
- Diamond and Carbon-based Materials Research
- Semiconductor materials and interfaces
- Thin-Film Transistor Technologies
- Iron-based superconductors research
- Advanced Surface Polishing Techniques
- Force Microscopy Techniques and Applications
- Laser Material Processing Techniques
- Magnetic properties of thin films
- Quantum, superfluid, helium dynamics
- Chemical and Physical Properties in Aqueous Solutions
- Advanced Electron Microscopy Techniques and Applications
- Magnetic and transport properties of perovskites and related materials
Centre de Nanosciences et de Nanotechnologies
2017-2024
Centre National de la Recherche Scientifique
2010-2023
Université Paris-Saclay
2017-2023
Université Paris-Sud
2008-2018
University of Cambridge
2013
Laboratoire de physique des Solides
2008-2009
L'Oréal (France)
1989
We report the design and measurement of Superconducting/normal/superconducting (SNS) proximity DC squids in long junction limit, i.e. superconducting loops interrupted by two normal metal wires roughly a micrometer long. Thanks to clean interface between metals, at low temperature large supercurrent flows through device. The dc squid-like geometry leads an almost complete periodic modulation critical current device magnetic flux, with flux periodicity quantum h/2e SNS loop. In addition, we...
Conventional spin-singlet Cooper pairs convert into spin-triplet in ferromagnetic Josephson junctions which the superconductor/ferromagnet interfaces (S/F) are magnetically inhomogeneous. Although much of theoretical work describing this triplet proximity effect has considered ideal with magnetic domain walls (DW) at interfaces, practice it is not easily possible to isolate a DW and propagate supercurrent through it. The rare-earth magnet Gd can form field-tuneable in-plane Bloch if grown...
We have measured the critical current dependence on magnetic flux of two long $SNS$ junctions differing by normal wire geometry. The samples are made a Au connected to W contacts, via focused ion beam assisted deposition. could tune pattern from monotonic Gaussian-like decay quasi-one-dimensional (1D) Fraunhofer-like square wire. explain limit with semiclassical 1D model, and we fit both field dependencies numerical simulations two-dimensional Usadel equations. Furthermore, observe integer...
A long phase coherent normal (N) wire between superconductors (S) is characterized by a dense dependent Andreev spectrum . We probe this in high frequency biased configuration, coupling an NS ring to multimode superconducting resonator. detect dc flux and response whose dissipative non components are related simple Debye relaxation law with characteristic time of the order diffusion through N part ring. The dependence exhibits $h/2e$ periodic oscillations large harmonics content at...
We investigate the critical temperature Tc of a thin s-wave superconductor (Nb) proximity coupled to helical rare earth ferromagnet (Ho). As function Ho layer thickness, we observe multiple oscillations superimposed on slow decay, that attribute influence Nb effect. Because inhomogeneous magnetization, singlet and triplet pair correlations are present in bilayers. take both into consideration when solving self consistent Bogoliubov-de Gennes equations, reasonable agreement. also non-trivial...
We report on the structural properties of highly B-doped silicon (> 2 at. %) realised by nanosecond laser doping. investigate crystalline quality, deformation and B distribution profile doped layer STEM analysis followed HAADF contrast studies GPA, compare results to SIMS analyses Hall measurements. When increasing active concentration above 4.3 at.%, fully strained, perfectly crystalline, Si:B starts showing dislocations stacking faults. These only disappear around 8 at.% when is well...
We use microwave excitation to elucidate the dynamics of long superconductor / normal metal Josephson junctions. By varying frequency in range 10 MHz - 40 GHz, we observe that critical and retrapping currents, deduced from dc voltage vs. current characteristics junction, are set by two different time scales. The increases when ac is larger than inverse diffusion metal, whereas strongly modified above electron-phonon rate metal. Therefore currents associated with elastic inelastic scattering,...
We report on the superconducting properties of a series heavily doped Si:B epilayers grown by gas immersion laser doping with boron content (${n}_{B}$) ranging from $\ensuremath{\sim}3\ifmmode\times\else\texttimes\fi{}{10}^{20}$ cm${}^{\ensuremath{-}3}$ to $\ensuremath{\sim}6\ifmmode\times\else\texttimes\fi{}{10}^{21}$cm${}^{\ensuremath{-}3}$ and thickness ($d$) varying between $\ensuremath{\sim}20$ nm $\ensuremath{\sim}210$ nm. show that superconductivity is only observed for ${n}_{B}$...
Superconducting boron-doped silicon is a promising material for integrated quantum devices. In particular, its low electronic density and moderate disorder make it suitable candidate the fabrication of large inductances with losses at microwave frequencies. We study experimentally electrodynamics superconducting thin layers using coplanar waveguide resonators, focusing on kinetic inductance, internal losses, variation these quantities resonator readout power. report observation in doped...
We have studied a Superconducting Quantum Interference Device (SQUID) made from single layer thin film of superconducting silicon. The is obtained by heavily doping silicon wafer with boron atoms using the gas immersion laser technique. SQUID composed two nano-bridges (Dayem bridges) in loop and shows magnetic flux modulation at low temperature field. overall behavior very good agreement numerical simulations based on Ginzburg-Landau equations.
Superconductivity in ultradoped Si 1− x Ge :B epilayers is demonstrated by nanosecond laser doping, which allows introducing substitutional B concentrations well above the solubility limit and up to 7 at%. A fraction ranging from 0 0.21 incorporated Si:B: 1) through a precursor gas, gas immersion doping; 2) ion implantation, followed annealing; 3) ultrahigh‐vacuum‐chemical vapor deposition growth of thin layer, annealing. The 30 75 nm‐thick display superconducting critical temperatures T c...
We have realised laser-doped all-silicon superconducting (S)/ normal metal (N) bilayers of tunable thickness and dopant concentration. observed a strong reduction the critical temperature when increasing thickness, signature highly transparent S/N interface associated to epitaxial sharp laser doping profile. extracted resistance by fitting with linearised Usadel equations, demonstrating one order magnitude from previous superconductor/doped Si interfaces. In this well controlled crystalline...
We achieved ohmic contacts down to 5 K on standard n-doped Ge samples by creating a strongly doped thin layer between the metallic and substrate. Thanks laser doping technique used, gas immersion doping, we could attain extremely large levels above solubility limit, thus reduce metal/doped contact resistance. tested independently influence of concentration thickness showed that improves when increasing level is not affected changing thickness. Furthermore, characterised Ge/Ge contact,...
In weakly spin-orbit coupled materials, the spin-selective nature of recombination can give rise to large magnetic-field effects, for example on electro-luminescence from molecular semiconductors. While silicon has weak coupling, observing spin-dependent through magneto-electroluminescence is challenging due inefficiency emission silicon's indirect band-gap, and difficulty in separating phenomena classical magneto-resistance effects. Here we overcome these challenges measure light-emitting...
Conducting nanowires possess remarkable physical properties unattainable in bulk materials. However our understanding of their transport is limited by the difficulty connecting them electrically. In this letter we investigate phototransport both silicon and using a superconducting multimode resonator operating at frequencies between 0.3 3 GHz. We find that whereas Si response mainly dissipative, exhibit large dielectric polarizability. This technique contactless can be applied to other...
Superconductivity in ultra-doped $Si_{1-x}Ge_{x}:B$ epilayers is demonstrated by nanosecond laser doping, which allows introducing substitutional B concentrations well above the solubility limit and up to $7\,at.\%$. A Ge fraction $x$ ranging from 0 0.21 incorporated $Si:B$ : 1) through a precursor gas Gas Immersion Laser Doping; 2) ion implantation, followed annealing; 3) UHV-CVD growth of thin layer, annealing. The 30 nm 80 thick display superconducting critical temperatures $T_c$ tuned...
We present superconducting monocrystalline silicon-on-insulator thin 33 nm epilayers. They are obtained by nanosecond laser annealing under ultra-high vacuum on 300 mm wafers heavily pre-implanted with boron (2.5 × 1016 at./cm2, 3 keV). Superconductivity is discussed in relation to the structural, electrical, and material properties, a step toward integration of ultra-doped Si at large scale. In particular, we highlight effect energy impact multiple anneals. Increasing leads linear increase...
Résumé La plupart des permanentes du commerce sont constituées d'acide thioglycolique (éventuellement associéà l'acide thiolactique), neutralisé par l'ammoniac, elles additionnées de carbonate d'ammonium comme tampon. Le système peut etre traité la neutralisation d'un mélange d'acides et carbonique il est complètement défini trois paramètres, concentrations, ou deux concentrations le pH, paramètres analytiques indépendants. Les calculs théoriques l'équilibre compliqués fait qu'il s'agit...