Vivek Mishra

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Iron-based superconductors could be useful for electricity distribution and superconducting magnet applications because of their relatively high critical current densities and upper critical fields. SmFeAsO₀.₈F₀.₁₅ is of particular interest as it has the highest transition temperature among these materials. Here we show that by introducing a low density of(More)
In superconductors with unconventional pairing mechanisms, the energy gap in the excitation spectrum often has nodes, which allow quasiparticle excitations at low energies. In many cases, such as in d-wave cuprate superconductors, the position and topology of nodes are imposed by the symmetry, and thus the presence of gapless excitations is protected(More)
Observations of robust superconductivity in some of the iron based superconductors in the vicinity of a Lifshitz point where a spin density wave instability is suppressed as the hole band drops below the Fermi energy raise questions for spin-fluctuation theories. Here we discuss spin-fluctuation pairing for a bilayer Hubbard model, which goes through such a(More)
The electrode gaps which results in to uniform electric fields are the most widely used gap configurations in assessing dielectric strength. In the present study simulation results of parallel plane electrode gap configurations with symmetrical and unsymmetrical supply are reported. When plane radius of plane electrode is reduced the plane electrode at its(More)
In the traditional Bardeen-Cooper-Schrieffer theory of superconductivity, the amplitude for the propagation of a pair of electrons with momentum k and -k has a log singularity as the temperature decreases. This so-called Cooper instability arises from the presence of an electron Fermi sea. It means that an attractive interaction, no matter how weak, will(More)
A single crystal of isovalently substituted Ba(Fe1−xRux)2As2 (x=0.24) is sequentially irradiated with 2.5 MeV electrons up to a maximum dose of 2.1×1019 e−/cm2. The electrical resistivity is measuredin situ at T=22 K during the irradiation and ex situ as a function of temperature between subsequent irradiation runs. Upon irradiation, the superconducting(More)
G. R. Boyd, T. P. Devereaux, 3 P. J. Hirschfeld, V. Mishra, and D. J. Scalapino Department of Physics, University of Florida, Gainesville, FL 32611, USA 2 Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 3 Geballe Laboratory for Advanced Materials, Departments of Physics(More)
In this paper, we study the boundary-induced phase transitions in a particle nonconserving asymmetric simple exclusion process with open boundaries. Using a boundary layer analysis on the mean field version of the model, we show that the key signatures of various bulk phase transitions are present in the boundary layers of the density profiles. In addition,(More)
The mechanism of unconventional superconductivity in iron-based superconductors (IBSs) is one of the most intriguing questions in current materials research. Among non-oxide IBSs, (Ba1-x K x )Fe2As2 has been intensively studied because of its high superconducting transition temperature and fascinating evolution of the superconducting gap structure from(More)
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