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

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1-Dimensional (1D) photonics crystals with and without defects have been numerically studied using efficient Transfer Matrix Method (TMM). Detailed numerical recipe of the TMM has been laid out. Dispersion relation is verified for the…

Classical Physics · Physics 2020-07-16 Shaolin Liao , Lu Ou

We have constructed MgB2/Pb planar junctions for both temperature and field dependence studies. Our results show that the small gap is a true bulk property of MgB2 superconductor, not due to surface effects. The temperature dependence of…

Superconductivity · Physics 2009-11-07 Mohamed H. Badr , Mario Freamat , Yuri Sushko , K. -W. Ng

The remarkable field dependence of the electronic thermal conductivity observed in MgB_2 can be explained as a consequence of multi-gap superconductivity. A key point is that for moderately clean samples, the mean free path becomes…

Superconductivity · Physics 2009-11-07 Hiroaki Kusunose , T. M. Rice , Manfred Sigrist

The superconducting-state heat capacity of Na$_{0.3}$CoO$_{2}$$\cdot$1.3H$_{2}$O shows unusual, marked deviations from BCS theory, at all temperatures. At low temperatures the heat capacity has the $T^2$ dependence characteristic of line…

Superconductivity · Physics 2007-05-23 N. Oeschler , R. A. Fisher , N. E. Phillips , J. E. Gordon , M. L. Foo , R. J. Cava

We report on tunneling spectroscopy experiments in small grains of the new binary intermetallic superconductor MgB2. Experiments have been performed at 2.5 K using a low temperature scanning tunneling microscope. Good fit to the BCS model…

Superconductivity · Physics 2009-11-07 Gabino Rubio-Bollinger , Hermann Suderow , Sebastian Vieira

To resolve the discrepancies of the superconducting order parameter in quasi-two-dimensional NbSe_2, comprehensive specific-heat measurements have been carried out. By analyzing both the zero-field and mixed-state data with magnetic fields…

Superconductivity · Physics 2009-11-13 C. L. Huang , J. -Y. Lin , Y. T. Chang , C. P. Sun , H. Y. Shen , C. C. Chou , H. Berger , T. K. Lee , H. D. Yang

The type I superconductor lead (Pb) has been theoretically predicted to be a two-band superconductor. We use scanning tunneling spectroscopy (STS) to resolve two superconducting gaps with an energy difference of 150$\,\mu$eV. Tunneling into…

Superconductivity · Physics 2015-04-22 Michael Ruby , Benjamin W. Heinrich , Jose I. Pascual , Katharina J. Franke

In this Letter we present new tunneling data on YBa$_2$Cu$_3$O$_7$ thin films by low temperature scanning tunneling spectroscopy. Unusual peak-dip-hump features, previously reported in Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$, are also found in…

Superconductivity · Physics 2009-10-31 T. Cren , D. Roditchev , W. Sacks , J. Klein

The tunneling spectra obtained within the ab-plane of Bi$_2$Sr$_2$CaCu$_2$O$_y$ (Bi2212) for temperatures below and above the critical temperature (T$_c$) are analyzed. We find that the tunneling conductance spectra for the underdoped…

Superconductivity · Physics 2009-11-07 Anjan K. Gupta , K. -W. Ng

We have measured the low-energy quasiparticle excitation spectrum of the electron doped high-temperature superconductors (HTS) Nd(1.85)Ce(0.15)CuO(4-y) and Pr(1.85)Ce(0.15)CuO(4-y) as a function of temperature and applied magnetic field…

Superconductivity · Physics 2009-11-07 S. Kleefisch , B. Welter , M. Naito , A. Marx , L. Alff , R. Gross

We investigated the local electronic density of states in superconductor-normal metal (Nb-Au) bilayers using a very low temperature (60 mK) STM. High resolution tunneling spectra measured on the normal metal (Au) surface show a clear…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 A. K. Gupta , L. Cretinon , N. Moussy , B. Pannetier , H. Courtois

High-resolution angle-resolved photoemission experiments reveal subtle modifications of the surface electronic structure of VSe2. Most remarkably, we show that superconductivity can be induced in VSe2 by the right selection of substrate and…

Superconductivity · Physics 2022-08-04 Turgut Yilmaz , Elio Vescovo , Jerzy T. Sadowski , Boris Sinkovic

We calculate the tunneling density of states (DOS) of MgB2 for different tunneling directions, by directly solving the real-axis, two-band Eliashberg equations (EE). Then we show that the numeric inversion of the standard single-band EE, if…

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

Superconducting micro-constrictions between Nb tips and high quality MgB$_{2}$ pellets have been realized by means of a point-contact inset, driven by a micrometric screw. Measurements of the current-voltage characteristics and of the…

A new technique permits high fidelity measurement of the tunneling density of states (TDOS) of the two-dimensional electron gas. The obtained TDOS contains no distortions arising from low 2D in-plane conductivity and includes the…

Mesoscale and Nanoscale Physics · Physics 2009-01-23 H. B. Chan , P. I. Glicofridis , R. C. Ashoori , M. L. Melloch

We present a comparison of electronic structure of MgB2 and TaB2, the two new superconductors, as well as VB2, calculated using full-potential, density- functional-based methods in P6/mmm crystal structure. Our results, described in terms…

Superconductivity · Physics 2007-05-23 Prabhakar P. Singh

The complex conductivity of a MgB2 film has been investigated in the frequency range 4 cm^{-1}< nu < 30 cm^{-1} and for temperatures 2.7 K < T <300 K. The overall temperature dependence of both components of the complex conductivity is…

Superconductivity · Physics 2009-11-07 A. V. Pronin , A. Pimenov , A. Loidl , S. I. Krasnosvobodtsev

The structural, electronic, optical and thermodynamic properties of Mo2Ga2C are investigated using density functional theory (DFT) within the generalized gradient approximation (GGA). The optimized crystal structure is obtained and the…

Materials Science · Physics 2017-04-18 M. A. Ali , M. R. Khatun , N. Jahan , M. M. Hossain

We present a Ginzburg-Landau theory for a two-band superconductor with emphasis on MgB$_{2}$. Experiments are proposed which lead to identification of the possible scenarios: whether both $\sigma $- and $\pi $-bands superconduct or $\sigma…

Superconductivity · Physics 2007-05-23 V. A. Ivanov , J. J. Betouras , F. M. Peeters

We report the specific heat (SH) measurements on single crystals of hole doped $FeAs$-based superconductor $Ba_{0.6}K_{0.4}Fe_2As_2$. It is found that the electronic SH coefficient $\gamma_e(T)$ is not temperature dependent and increases…

Superconductivity · Physics 2009-05-02 Gang Mu , Huiqian Luo , Zhaosheng Wang , Lei Shan , Cong Ren , Hai-Hu Wen