Analytical study of properties of holographic superconductors with   exponential nonlinear electrodynamics
  Based on the Sturm-Liouville (SL) eigenvalue problem, we analytically study several properties of holographic $s$-wave superconductors with exponential nonlinear electrodynamics in the background of Schwarzschild anti-de Sitter (AdS) black holes. We assume the probe limit in which the scalar and gauge fields do not back react on the background metric. We show that for this system, one can still obtain an analytical relation between the critical temperature and the charge density. Interestingly enough, we find that logarithmic nonlinear electrodynamics decreases the critical temperature, $T_c$, of the holographic superconductors compared to the linear Maxwell field. This implies that the nonlinear electrodynamics make the condensation harder. The analytical results obtained in this paper are in good agreement with the existing numerical results. We also compute the critical exponent near the critical temperature and find out that it is still $1/2$ which seems to be an universal value in mean field theory. 
A. Sheykhi and F. Shaker
hep-th