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Related papers: Two Gap State Density in MgB$_{2}$: A True Bulk Pr…

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X-ray emission (XES) and absorption (XAS) spectra near the B-$K$ edge were measured on single-crystalline AlB$_2$ compound which is an isostructural diboride of superconducting MgB$_2$. The partial density of states (PDOS) of B-2$p\sigma$…

Using a Scanning Tunneling Microscope (STM), we investigate the Local Density of States (LDOS) of artificially fabricated normal metal nano-structures in contact with a superconductor. Very low temperature local spectroscopic measurements…

Mesoscale and Nanoscale Physics · Physics 2015-06-25 W. Escoffier , C. Chapelier , F. Lefloch

PtPb$_4$ is a type II superconductor with a bulk critical temperature $T_{c}\approx 3 $K and an upper critical field of $H_{c2}=0.36 $T. PtPb$_4$ is related to non-superconducting PtSn$_4$, which presents nodal arc states at the surface.…

We investigated a high-quality MgB$_{2}$ thin film with a thickness of $\sim$1000 nm on an Al$_{2}$O$_{3}$ substrate using optical spectroscopy. We measured the reflectance spectra of the film at various temperatures both below, and above,…

Superconductivity · Physics 2018-08-21 Yu-Seong Seo , Jae Hak Lee , Won Nam Kang , Jungseek Hwang

We present a method to produce superconducting tips to be used in Scanning Tunneling Microscopy/Spectroscopy experiments. We use these tips to investigate the evolution of the electronic density of states of NbSe2 from 0.3K up to its…

Superconductivity · Physics 2009-11-10 J. G. Rodrigo , S. Vieira

We have performed high-resolution photoemission spectroscopy on MgB2 and observed opening of a superconducting gap with a narrow coherent peak. We found that the superconducting gap is s-like with the gap value of 4.5 meV at 15 K. The…

Strongly Correlated Electrons · Physics 2009-11-07 T. Takahashi , T. Sato , S. Souma , T. Muranaka , J. Akimitsu

In the present work we calculate the tunneling density of states (DOS) of MgB% $_{2}$ for different tunneling directions by directly solving the two-band Eliashberg equations (EE) in the real-axis formulation. This procedure reveals the…

Superconductivity · Physics 2009-11-10 O. V. Dolgov , R. S. Gonnelli , G. A. Ummarino , A. A. Golubov , S. V. Shulga , J. Kortus

Interlayer tunneling resistivity is used to probe the low-energy density-of-states (DOS) depletion due to the pseudogap in the normal state of Bi$_2$Sr$_2$CaCu$_2$O$_{8+y}$. Measurements up to 60 T reveal that a field that restores DOS to…

Superconductivity · Physics 2009-11-07 T. Shibauchi , L. Krusin-Elbaum , Ming Li , M. P. Maley , P. H. Kes

Semiclassical theory of proximity effect predicts a gap E_g \sim hD/L^2 in the excitation spectrum of a long diffusive SNS junction. Mesoscopic fluctuations lead to anomalously localized states in the normal part of the junction. As a…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 P. M. Ostrovsky , M. A. Skvortsov , M. V. Feigel'man

Experimental support is found for the multiband model of the superconductivity in the recently discovered system MgB2 with the transition temperature Tc = 39 K. By means of Andreev reflection evidence is obtained for two distinct…

Superconductivity · Physics 2009-02-12 P. Szabo , P. Samuely , J. Kacmarcik , Th. Klein , J. Marcus , D. Fruchart , S. Miraglia , C. Marcenat , A. G. M. Jansen

We report specific heat measurements in neutron irradiated MgB2 samples, for which the critical temperature has been suppressed down to 8.5 K, but the superconducting transition remains extremely sharp, indicative of a defect structure…

Superconductivity · Physics 2009-11-11 M. Putti , M. Affronte , C. Ferdeghini , C. Tarantini , E. Lehmann

We present resistivity and thermal conductivity measurements on bulk samples, prepared either by a standard method or by a one-step technique. The latter samples, due to their high density and purity, show residual resistivity values as low…

Superconductivity · Physics 2009-11-07 M. Putti , V. Braccini , E. Galleani , F. Napoli , I. Pallecchi , A. S. Siri , P. Manfrinetti , A. Palenzona

Scanning tunneling microscopy/spectroscopy (STM/STS) measurements were carried out on a multi-layered cuprate superconductor Ba$_2$Ca$_5$Cu$_6$O$_{12}$(O$_{1-x}$,F$_x$)$_2$. STM topography revealed random spot structures with the…

We study the influence of Fermi surface topology on the quasiparticle density of states in the vortex state of type II superconductors. We observe that the field dependence and the shape of the momentum and spatially averaged density of…

Superconductivity · Physics 2007-05-23 S. Graser , T. Dahm , N. Schopohl

We investigate strong-coupling effects on normal state properties of an ultracold Fermi gas. Within the framework of $T$-matrix approximation in terms of pairing fluctuations, we calculate the single-particle density of states (DOS), as…

Quantum Gases · Physics 2013-05-29 Shunji Tsuchiya , Ryota Watanabe , Yoji Ohashi

We present thermal conductivity and specific heat measurements on MgB2 and Mg-AlB2 samples. Thermal properties have been analysed by using a two-gap model in order to estimate the gap amplitudes, D(0)p and D(0)s and the intra-band…

Superconductivity · Physics 2009-11-10 M. Putti , E. Galleani , I. Pallecchi , C. Bernini , P. Manfrinetti , A. Palenzona , M. Affronte

Far-infrared reflectivity studies on the polycrystalline intermetallic compound MgB_2 with a superconducting transition temperature T_c=39 K were performed at temperatures 20 K to 300 K. We observe a significant raise of the…

We performed the local spectroscopy of a Normal-metal--Superconductor (N-S) junction with the help of a very low temperature (60 mK) Scanning Tunneling Microscope (STM). The spatial dependence of the local density of states was probed…

Superconductivity · Physics 2009-11-07 N. Moussy , H. Courtois , B. Pannetier

The theory of thermodynamic properties of two-band superconductor with reduced density charge carriers is developed on the base of phonon superconducting mechanism with strong electron-phonon interaction. This theory is adapted to describe…

Superconductivity · Physics 2015-06-25 M. E. Palistrant , V. A. Ursu

The single-particle density of states and the tunneling conductance are studied for a two-dimensional BCS-like Hamiltonian with a d_{x^2-y^2}-gap and phase fluctuations. The latter are treated by a classical Monte Carlo simulation of an XY…

Superconductivity · Physics 2009-11-07 T. Eckl , D. J. Scalapino , E. Arrigoni , W. Hanke