Maximization of a Superconductor's Transition Temperature in a Boson - Fermion Model by Variation of the Boson Density of States and the Boson - Fermion Coupling Constants or for Spin Vector or Scalar Couplings Respective
ORAL
Abstract
We have solved the problem of maximizing a superconductors transition temperature $T_c $ by varying the Boson (spin fluctuation or phonon) density of states $N_B \left( \omega \right)$ and coupling constants, $J_q $ or$g_{kq\lambda } $. We find that $T_c \sim 10^9\;{ }^0K$ can be obtained, for example in Heusler alloys, such as$Au_2 \left( {Mn_{2-x} \;A\ell _x } \right)$, with$x\sim 0.1-0.5$. Also values of $H_{c2} \sim 10^{13}T$ and$j_c \sim 10^{13}\,Amps/cm^2$are predicted. Additionally results for the tunneling density of states$N_T \left( {eV} \right)$, the arpes cross section,${d\Delta } \mathord{\left/ {\vphantom {{d\Delta } {d\Omega d\omega }}} \right. \kern-\nulldelimiterspace} {d\Omega d\omega }$, $e.m.,{\kern 1pt}\,I.R.$ and transport coefficients arising from these models will be presented. Also we will present a discussion of the 36 Leggett modes which our theory predicts to exist, whose energies are in the optical frequency range$\left[ {\omega \sim 1-3eV} \right]$, versus the microwave frequency range for superfluid $^{3}$He-A phase.
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Authors
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Arno Kampf
Institut fur Physik, University of Augusburg, D-86135 Augsburg Germany
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Robert Schrieffer
Department of Physics and National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, Physics Department and National High Magnetic Field Lab, Florida State University, Tallahassee, FL 32310., National High Magnetic Field Laboratory and Department of Physics, Florida State University, Tallahassee, FL 32310