相关论文: MgB2: superconductivity and pressure effects
The discovery of superconductivity in Magnesium Diborate (MgB$_2$) has stimulated great interest in the search of new superconductors with similar lattice structures. Unlike cuprate or iron-based superconductors, MgB$_2$ is indisputably a…
We present thermal conductivity measurements on very pure and dense bulk samples, as indicated by residual resistivity values as low as 0.5 mW cm and thermal conductivity values higher than 200 W/mK. In the normal state we found that the…
The recently discovered superconductivity in MgB2 has created the world sensation. In spite of the relatively high superconducting transition temperature Tc=39K, the superconductivity is understood in terms of rare two gap superconductor…
First principles FLMTO-GGA electronic structure calculations of the new medium-$T_C$ superconductor (MTSC) $MgB_2$ and related diborides indicate that superconductivity in these compounds is related to the the existence of $p_{x,y}$-band…
We consider the dependence of the MgB_2 superconducting critical temperature on the pressure. Our model exploits the influence of the large polarons on the band structure of the layered MgB_2 superconductor. Namely, the hole Pekar-Froehlich…
It is shown that the superconducting intermetallic compound MgB2 possesses a narrow, partly filled "superconducting band" with Wannier functions of special symmetry in its band structure. This result corroborates previous observations about…
We present a systematic study of the response properties of two-band (multi-gap) superconductors with spin-singlet (s-wave) pairing correlations, which are assumed to be caused by both intraband (\lambda_{ii}, i=1,2) and interband…
Detailed temperature dependence of both superconducting gaps was obtained directly by means of SnS-Andreev spectroscopy. The \Delta \sigma,\pi(T) -curves were shown to be deviated from standard BCS-like behavior, due to k-space proximity…
The magnetic coupling between two concentric mesoscopic superconductors with non-zero thickness is studied using the nonlinear Ginzburg-Landau theory. We calculated the free energy, the expelled field, the total field profile, the…
We propose a novel mechanism of superconductivity in MgB$_2$ based on the dynamic electronic structure of the $p\sigma$-orbitals coupled with $e_{2g}$ phonons. A nonconventional superconducting state is found to arise frome lectron-phonon…
Considerable excitement has been caused recently by the discovery that the binary boride system with stoichiometry MgB2 is superconducting at the remarkably high temperature of 39 K (1). This potentially opens the way to even higher Tc…
LiB, a predicted layered compound analogous to the MgB$_2$ superconductor, has been recently synthesized via cold compression and quenched to ambient pressure, yet its superconducting properties have not been measured. According to prior…
A simple two-band model with interband scattering of intraband pairs is applied to MgB$_2$ superconductivity. An adjustable parameters set is chosen. The calculated $T_c$ vs doping, isotope exponent and the heat capacity jump are in…
The superconducting state of an infinitely long superconducting cylinder surrounded by a medium which enhances its superconductivity near the boundary is studied within the nonlinear Ginzburg-Landau theory. This enhancement can be due to…
We report magnetic field dependent magnetization and microwave impedance measurements on a MgB2 superconductor prepared by high pressure synthesis. We find that the upper critical field is linearly dependent on temperature near Tc and the…
The specific heat C of a sintered polycrystalline sample of MgB2 with a bulk superconducting transition temperature Tc=36.7 K is measured as a function of the temperature (2-300 K) and magnetic field (0-16 T), together with magnetic…
We characterize the superconducting state of phase pure polycrystalline samples of the new layered superconductor MgB$_2$ by specific heat measurements in magnetic fields up to 9 T. The characteristic jump at the superconducting transition…
The recently discovered multiband superconductors have created a new class of novel superconductors. In these materials multiple superconducting gaps arise due to the formation of Cooper pairs on different sheets of the Fermi surfaces. An…
The electromagnetic properties of superconductors near a ferromagnetic instability are investigated by means of a generalized Ginzburg-Landau theory. It is found that the magnetic flux expulsion capability of the superconductor gets…
Two-band superconductivity has become an important topic over the last ten years. Extensive experimental and theoretical studies started with MgB2 and are now focused on the iron-based and other new superconductors. In this review, I…