Flux-line tilt moduli in anisotropic superconductors

A general expression for the elastic energy of the flux-line lattice (FLL) in anisotropic superconductors is given. From this we derive three tilt moduli ${\mathit{c}}_{44}$(k) for the FLL in uniaxial superconductors with induction B∥ and ⊥ to the basal plane. The discreteness of the FLL leads to a logarithmically dispersive isolated-vortex term, which at B≪${\mathit{B}}_{\mathit{c}2}$ in a large part of the Brillouin-zone area exceeds the usual Lorentzian-dispersive ${\mathit{c}}_{44}$(k) originating from the overlapping vortex fields. The difference between vortex self-energy, line tension, and tilt modulus in an anisotropic superconductor is discussed.