A5000516095- Physics of Superconductivity and Magnetism
- Quantum and electron transport phenomena
- Advanced Condensed Matter Physics
- Advancements in Semiconductor Devices and Circuit Design
- Semiconductor Quantum Structures and Devices
- Magnetic and transport properties of perovskites and related materials
- Quantum Information and Cryptography
- Rare-earth and actinide compounds
- Integrated Circuits and Semiconductor Failure Analysis
- Organic and Molecular Conductors Research
- Cold Atom Physics and Bose-Einstein Condensates
- Superconducting Materials and Applications
- Quantum optics and atomic interactions
- Mechanical and Optical Resonators
- Advanced Electrical Measurement Techniques
- Superconductivity in MgB2 and Alloys
- Quantum Mechanics and Applications
- Advanced Thermodynamics and Statistical Mechanics
- Surface and Thin Film Phenomena
- High-pressure geophysics and materials
- Inorganic Fluorides and Related Compounds
- Topological Materials and Phenomena
- Scientific Research and Discoveries
- Superconducting and THz Device Technology
- Semiconductor materials and devices
Université de Sherbrooke
2016-2025
The University of Tokyo
2007
Tokyo University of Science
2007
Kyoto University Institute for Chemical Research
2007
Cornell University
2004-2007
RIKEN
2007
Kyoto Bunkyo University
2007
Kyoto University
2007
University of Toronto
2000-2004
University of California, Berkeley
2003
Removing electrons from the CuO2 plane of cuprates alters electronic correlations sufficiently to produce high-temperature superconductivity. Associated with these changes are spectral weight transfers high energy states insulator low energies. In theory, should be detectable as an imbalance between tunneling rate for electron injection and extraction - a asymmetry. We introduce atomic-resolution tunneling-asymmetry imaging, finding virtually identical phenomena in two lightly hole-doped...
Heat transport in the cuprate superconductors YBa$_2$Cu$_3$O$_{y}$ and La$_{2-x}$Sr$_x$CuO$_4$ was measured at low temperatures as a function of doping. A residual linear term kappa_{0}/T is observed throughout superconducting region it decreases steadily Mott insulator approached from overdoped regime. The low-energy quasiparticle gap extracted seen to scale closely with pseudogap. ubiquitous presence nodes tracking pseudogap shows that overall remains pure d-wave form phase diagram, which...
A residual linear term is observed in the thermal conductivity of optimally doped ${\mathrm{Bi}}_{2}{\mathrm{Sr}}_{2}{\mathrm{CaCu}}_{2}{\mathrm{O}}_{8}$ at very low temperatures whose magnitude excellent agreement with value expected from Fermi-liquid theory and d-wave energy spectrum measured by photoemission spectroscopy no adjustable parameters. This solid basis allows us to make a quantitative analysis thermodynamic properties temperature establish that thermally excited quasiparticles...
We present a study of the electronic ultrasound attenuation alpha in unconventional superconductor Sr(2)RuO(4). The power law behavior at temperatures down to T(c)/30 clearly indicates presence nodes gap. In normal state, we find an enormous anisotropy basal plane tetragonal structure. superconducting temperature dependence also exhibits significant anisotropy. discuss these results relation possible gap functions.
To establish the mechanism of unconventional superconductivity in Sr${}_{2}$RuO${}_{4}$, a prerequisite is direct information concerning momentum-space structure energy gaps ${\ensuremath{\Delta}}_{i}(k)$, and particular whether pairing strength stronger (``dominant'') on quasi-one-dimensional ($\ensuremath{\alpha}$ $\ensuremath{\beta}$) or quasi-two-dimensional ($\ensuremath{\gamma}$) Fermi surfaces. We present scanning tunneling microscopy measurements density states spectra...
The temperature dependence of the electrical resistivity along a and b axes ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{6.9}$ has been measured in high-purity fully detwinned single crystals. Below 300 K, ${\mathrm{\ensuremath{\rho}}}_{\mathit{a}}$(T) was found to be perfectly linear, while ${\mathrm{\ensuremath{\rho}}}_{\mathit{b}}$(T) revealed distinct upward curvature. Viewing b-axis conductivity as sum conductivities ${\mathrm{CuO}}_{2}$ planes Cu-O chains, ${\mathit{T}}^{2}$...
The effect of vortices on quasiparticle transport in cuprate superconductors was investigated by measuring the low temperature thermal conductivity YBa_2Cu_3O_6.9 magnetic fields up to 8 T. residual linear term (as T \to 0) is found increase with field, directly reflecting occupation extended states. A study for different Zn impurity concentrations reveals a good agreement recent calculations d-wave superconductor, thereby shedding light nature scattering both impurities and vortices. It...
The thermal conductivity of borocarbide superconductor $\mathrm{LuNi}{}_{2}{\mathrm{B}}_{2}\mathrm{C}$ was measured down to 70 mK $({T}_{c}/200)$ in a magnetic field perpendicular the heat current from $H\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0$ above ${H}_{c2}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}7\phantom{\rule{0ex}{0ex}}\mathrm{T}$. As soon as vortices enter sample, conduction at $T\ensuremath{\rightarrow}0$ grows rapidly, showing unambiguously that delocalized...
We report the measurement of fluctuations two quadratures electromagnetic field generated by a quantum conductor, dc- and ac-biased tunnel junction placed at very low temperature. observe that variance on one quadrature can go below vacuum, i.e., radiated is squeezed. This demonstrates nature field.
We report the measurement of current noise a tunnel junction driven out-of-equilibrium by temperature and/or voltage difference, i.e. charge heat electrical current. This is achieved careful control electron below 1 K at nanoscale, and sensitive with wide bandwidth, from 0.1 to GHz. An excellent agreement between experiment theory no fitting parameter obtained. In particular, we find that resistance R when one electrode T other zero given S = 2 ln2 kB /R.
We report measurements of the correlations between electromagnetic field quadratures at two frequencies f1=7 GHz and f1=7.5 radiation emitted by a tunnel junction placed very low temperature excited frequency f1+f2. demonstrate existence two-mode squeezing violation Bell-like inequality, thereby proving entanglement in quantum shot noise radiated junction.Received 23 October 2014DOI:https://doi.org/10.1103/PhysRevLett.114.130403© 2015 American Physical Society
Generation and control of non-classical electromagnetic fields is crucial importance for quantum information physics. While usual methods the production such rely on a non-linearity (of crystal, Josephson junction, etc.), recent experiment performed normal conductor, tunnel junction under microwave irradiation, has unveiled an alternative: use electron shot noise in conductor\cite{PAN_squeezing}. Here we show that device can emit \emph{pairs photons} different frequencies with rate as high...
The transport of heat and charge in cuprates was measured single crystals La(2-x)Sr(x)CuO(4+delta) (LSCO) across the doping phase diagram at low temperatures. In underdoped LSCO, thermal conductivity is found to decrease with increasing magnetic field T-->0 limit, striking contrast increase observed all superconductors, including higher doping. heavily where superconductivity can be entirely suppressed an applied field, we show that a novel metal-to-insulator transition takes place upon...
The thermal conductivity of ultraclean YBa2Cu3O7 was measured at very low temperature in magnetic fields up to 13 T. and field dependence the electronic heat show that two widespread assumptions transport theory applied unconventional superconductors fail for clean cuprates: impurity scattering cannot be treated usual unitary limit (nor indeed Born limit), quasiparticles off vortices neglected. Our study also sheds light on long-standing puzzle a sudden onset "plateau" Bi-2212 versus field.
The six independent elastic constants of ${\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4}$ were determined using resonant ultrasound spectroscopy on a high-quality single-crystal specimen. are in excellent agreement with those obtained from pulse-echo experiments performed sample cut the same ingot. A calculation Debye temperature measured agrees well values both specific heat and M\"ossbauer measurements.
Temporal correlations between electrons reveal that crossing a conductor at low temperature cross it regular pace $h/e\phantom{\rule{0}{0ex}}V$ with jitter $h/{k}_{B}\phantom{\rule{0}{0ex}}T$, thus providing simple picture of why and how current fluctuates.
Charge density waves (CDWs) in the second and third Landau levels (LLs) are investigated by both nonlinear electronic transport noise. The use of a Corbino geometry ensures that only bulk properties probed, with no contribution from edge states. Sliding CDWs is revealed narrow band noise reentrant quantum Hall states $R2a$ $R2c$ LL, as well pinned LL. Competition between various phases---stripe, CDW, or fractional liquid---in LLs clearly combining data maps conductivity versus magnetic field...
Abstract We propose an approach to detailed balance violation in electrical circuits based on the scattering matrix formalism commonly used microwave electronics. This allows us easily include retardation effects, which are paramount at high frequencies. define spectral densities of phase space angular momentum, heat transfer and cross power, can serve as criteria for violation. confirm our theory with measurements 4–8 GHz frequency range several two port varying symmetries, time. validates...
We report measurements of the low frequency current fluctuations a tunnel junction placed at very temperature biased by time-dependent voltage $V(t)=V(1+\cos 2\pi\nu t)$. observe that excess noise generated ac excitation exhibits quantum oscillations as function dc bias, with period given $h\nu/e$ $e$ charge single electron. This is direct consequence nature electricity in normal conductor.
Photocount statistics are an important tool for the characterization of electromagnetic fields, especially fields with irrelevant phase. In microwave domain, continuous rather than discrete measurements norm. Using a novel approach, we recover photon from cumulants distribution field quadrature measurements. The use allows separation between signal interest and experimental noise. parametric amplifier as first stage amplification chain, extract useful data up to sixth cumulant coherent...