Abstract
We reconsider microscopically and thermodynamically the heat current associated with the motion of vortex lines in a dirty type-II superconductor and show that the heat-current operator j0h employed previously by Caroli and Maki has to be replaced by jh in the presence of a constant magnetic field H:jh=j0h+HjM, where jM may be called the magnetization current. We then recalculate the entropy associated with a single vortex line SD at all temperatures (and in the high-field region), which vanishes like T at low temperatures.