Christian Lupien

An intrinsic bond-centered electronic glass with unidirectional domains in underdoped cuprates.

Removing electrons from the CuO2 plane of cuprates alters the electronic correlations sufficiently to produce high-temperature superconductivity. Associated with these changes are spectral-weight transfers from the high-energy states of the insulator to low energies. In theory, these should be detectable as an imbalance between the tunneling rate for electron injection and extraction—a tunneling asymmetry. We introduce atomic-resolution tunneling-asymmetry imaging, finding virtually identical phenomena in two lightly hole-doped cuprates: Ca1.88Na0.12CuO2Cl2 and Bi2Sr2Dy0.2Ca0.8Cu2O8+δ. Intense spatial variations in tunneling asymmetry occur primarily at the planar oxygen sites; their spatial arrangement forms a Cu-O-Cu bond-centered electronic pattern without long-range order but with 4a0-wide unidirectional electronic domains dispersed throughout (a0: the Cu-O-Cu distance). The emerging picture is then of a partial hole localization within an intrinsic electronic glass evolving, at higher hole densities, into complete delocalization and highest-temperature superconductivity.

Thermal conductivity across the phase diagram of cuprates: Low-energy quasiparticles and doping dependence of the superconducting gap

Heat transport in the cuprate superconductors

Low-energy quasiparticles in cuprate superconductors: A quantitative analysis

{\mathrm{YBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{y}

Highly Anisotropic Gap Function in Borocarbide Superconductor LuNi2B2C

and

Quasiparticle Transport in the Vortex State of YBa 2 Cu 3 O 6.9

{\mathrm{La}}_{2\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{CuO}}_{4}

Piezoresistive torque magnetometry below 1 K

was measured at low temperatures as a function of doping. A residual linear term

Experimental violation of bell-like inequalities by electronic shot noise.

{\ensuremath{\kappa}}_{0}/T

Observation of squeezing in the electron quantum shot noise of a tunnel junction.

is observed throughout the superconducting region and it decreases steadily as the Mott insulator is approached from the overdoped regime. The low-energy quasiparticle gap extracted from

Emission of microwave photon pairs by a tunnel junction.

{\ensuremath{\kappa}}_{0}/T

Observation of quantum oscillations in the photoassisted shot noise of a tunnel junction

is seen to scale closely with the pseudogap. The ubiquitous presence of nodes and the tracking of the pseudogap shows that the overall gap remains of the pure d-wave form throughout the phase diagram, which excludes the possibility of a complex component