Defect pair in the elastic lattice of pancake vortices

An additional pancake-antipancake vortex pair is considered in the vortex lattice of layered superconductors. Within linear elastic continuum theory, the relaxation of the background lattice screens the long-range logarithmic interaction of the defect pair, reducing the factor (Formula presented) to (Formula presented) where (Formula presented) is the pair spacing, (Formula presented) the in-plane coherence length, and (Formula presented) the vortex spacing. The finite tilt modulus does not destroy this ideal two-dimensional screening, yielding a small correction (Formula presented), which in principle is of long range, but has a very small prefactor when the vortex spacing (Formula presented) is smaller than the in-plane penetration depth (Formula presented).