arXiv subjects

M. Juneau

Publications and source records attributed to M. Juneau.

2 recordsLinked to original sources

arXiv2002

Magnetic properties of SO(5) superconductivity

The distinction between type I and type II superconductivity is re-examined in the context of the SO(5) model recently put forth by Zhang. Whereas in conventional superconductivity only one parameter (the Ginzburg-Landau parameter $κ$) characterizes the model, in the SO(5) model there are two essential parameters. These can be chosen to be $κ$ and another parameter, $β$, related to the doping. There is a more complicated relation between $κ$ and the behavior of a superconductor in a magnetic field. In particular, one can find type I superconductivity, even when $κ$ is large, for appropriate values of $β$.

cond-mat↗

arXiv2001

Vortex lattice stability in the SO(5) model

We study the energetics of superconducting vortices in the SO(5) model for high-$T_c$ materials proposed by Zhang. We show that for a wide range of parameters normally corresponding to type II superconductivity, the free energy per unit flux $\FF(m)$ of a vortex with $m$ flux quanta is a decreasing function of $m$, provided the doping is close to its critical value. This implies that the Abrikosov lattice is unstable, a behaviour typical of type I superconductors. For dopings far from the critical value, $\FF(m)$ can become very flat, indicating a less rigid vortex lattice, which would melt at a lower temperature than expected for a BCS superconductor.

cond-mat.supr-con↗