DEFECT PAIR IN THE ELASTIC LATTICE OF PANCAKE VORTICES

An additional pancake-antipancake vortex pair is considered in the vor tex lattice of layered superconductors. Within linear elastic continuu m theory, the relaxation of the background lattice screens the long-ra nge logarithmic interaction of the defect pair, reducing the factor ln (r(0)/xi) to In(a/epsilon) where r(0) is the pair spacing, xi the in-p lane coherence length, and a the vortex spacing. The finite tilt modul us does not destroy this ideal two-dimensional screening, yielding a s mall correction similar to(a(2)/8 pi lambda(2))ln(r(0)/a), which in pr inciple is of long range, but has a very small prefactor when the vort ex spacing a is smaller than the in-plane penetration depth lambda.