Pierre Rodiere

Superconducting Density of States and Vortex Cores of 2H-NbS2

Scanning tunneling microscopy and spectroscopy measurements in the superconducting dichalcogenide 2H-NbS2 show a peculiar superconducting density of states with two well-defined features at 0.97 and 0.53 meV, located, respectively, above and below the value for the superconducting gap expected from the single band s-wave BCS model (Delta=1.76k_(B)T_(c)=0.9 meV). Both features have a continuous temperature evolution and disappear at T_(c)=5.7 K. Moreover, we observe the hexagonal vortex lattice with radially symmetric vortices and a well-developed localized state at the vortex cores. The sixfold star shape characteristic of the vortex lattice of the compound 2H-NbSe2 is, together with the charge density wave order, absent in 2H-NbS2.

The Diamond Superconducting Quantum Interference Device

Diamond is an electrical insulator in its natural form. However, when doped with boron above a critical level (∼0.25 atom %) it can be rendered superconducting at low temperatures with high critical fields. Here we present the realization of a micrometer-scale superconducting quantum interference device (μ-SQUID) made from nanocrystalline boron-doped diamond (BDD) films. Our results demonstrate that μ-SQUIDs made from superconducting diamond can be operated in magnetic fields as large as 4 T independent of the field direction. This is a decisive step toward the detection of quantum motion in a diamond-based nanomechanical oscillator.Soumen Mandal ∗ , Tobias Bautze, Oliver A. Williams, Cécile Naud, Étienne Bustarret, Franck Omnès, Pierre Rodière, Tristan Meunier, Christopher Bäuerle ∗ , and Laurent Saminadayar Institut Néel, CNRS et Université Joseph Fourier, F-38042 Grenoble, France Fraunhofer-Institut für Angewandte Festkörperphysik, Tullastraße 72, 79108 Freiburg, Germany and Institut Universitaire de France, 103 boulevard Saint-Michel, 75005 Paris, France

Thermodynamic phase diagram of Fe(Se0.5Te0.5) single crystals in fields up to 28 tesla

We report on specific heat

Pressure dependence of superconducting critical temperature and upper critical field of 2H-NbS2

({C}_{p})

Nanostructures made from superconducting boron-doped diamond

, transport, Hall probe, and penetration depth measurements performed on

Strong anharmonicity induces quantum melting of charge density wave in 2H-NbSe

\text{Fe}({\text{Se}}_{0.5}{\text{Te}}_{0.5})

_2

single crystals

under pressure

({T}_{c}\ensuremath{\sim}14\text{ }\text{K})

Strong enhancement of superconductivity at high pressures within the charge-density-wave states of 2H-TaS 2 and 2H-TaSe 2

. The thermodynamic upper critical field

Superconducting nano-mechanical diamond resonators

{H}_{c2}