Vortex-induced strain and flux lattices in anisotropic superconductors

Abstract

Strains in superconductors that accompany vortex nucleation and arise due to the difference in the specific volumes of the superconducting and normal phases are evaluated. The strain in anisotropic materials causes an extra intervortex interaction, which is long range as compared to a stronger but finite-range London force. In materials with a strong pressure dependence of superconductivity (such as ${\mathrm{NbSe}}_{2}$) the strain-induced interaction affects the structure of the flux lattices. For the field parallel to the c axis of ${\mathrm{NbSe}}_{2}$ the flux lattice is locked on the crystal, a fact that cannot be explained either by London or by harmonic elastic interactions. The possible role of anharmonic elastic interactions of vortices for this case is discussed.