Phase transition induced by a magnetic field
  The magnetic catalysis of discrete chiral symmetry breaking in the 2+1 dimensional Nambu-Jona-Lasinio model is analyzed. A particular attention is paid to a possible application of the effect in solid state physics. The fermion contribution to the thermal conductivity as a function of the dynamical mass (energy gap in the spectrum) is estimated and is shown to be suppressed when a non-zero order parameter develops. 
G. W. Semenoff, I. A. Shovkovy and L. C. R. Wijewardhana