منابع مشابه
Origin of superconductivity transition broadening in MgB2
We report resistivity and magnetization of single crystal MgB2, focusing on the broadening of superconducting (SC) transition in magnetic fields. In-plane and outof-plane resistivity indicate that the broadening of superconducting transition is independent of Lorentz force and that it is merely dependent on the magnetic field direction. In magnetization, diamagnetic signal begins to appear at a...
متن کاملMgB2: superconductivity and pressure effects
The Ginzburg-Landau theory is presented for a two-band superconductor with emphasis on MgB2. Experiments are proposed which lead to identification of the possible scenarios: whether both σand π-bands superconduct or σ-alone. According to the second scenario a microscopic theory of superconducting MgB2 is proposed based on the strongly interacting σ-electrons and non-correlated π-electrons of bo...
متن کاملSuperconductivity in MgB2: clean or dirty?
A large number of experimental facts and theoretical arguments favor a two-gap model for superconductivity in MgB2. However, this model predicts strong suppression of the critical temperature by interband impurity scattering and, presumably, a strong correlation between the critical temperature and the residual resistivity. No such correlation has been observed. We argue that this fact can be u...
متن کاملRVB Contribution to Superconductivity in MgB2
We view MgB2 as electronically equivalent to (non-staggered) graphite (B − layer) that has undergone a zero gap semiconductor to a superconductor phase transition by a large c-axis (chemical) pressure due to Mg layers. Further, like the pπ bonded planar organic molecules, graphite is an old resonating valence bond (RVB) system. The RVB’s are the ‘preexisting cooper pairs’ in the ‘parental’ zero...
متن کاملSuperconductivity of metallic boron in MgB2.
Boron in MgB2 forms stacks of honeycomb layers with magnesium as a space filler. Band structure calculations indicate that Mg is substantially ionized, and the bands at the Fermi level derive mainly from B orbitals. Strong bonding with an ionic component and considerable metallic density of states yield a sizable electron-phonon coupling. Together with high phonon frequencies, which we estimate...
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ژورنال
عنوان ژورنال: Solid State Communications
سال: 2006
ISSN: 0038-1098
DOI: 10.1016/j.ssc.2006.03.036