LOCAL-DENSITY OF STATES IN THE VORTEX LATTICE IN A TYPE-II SUPERCONDUCTOR

The local density of states (LDOS) in the triangular vortex lattice is investigated based on quasiclassical Eilenberger theory. We consider the case of an isotropic s-wave superconductor with the material param eter appropriate to NbSe2. At a weak magnetic held, the spatial Variat ion of the LDOS shows a cylindrical structure around a vortex core. On the other hand, at a high held where the core regions substantially o verlap each other, the LDOS is a sixfold star-shaped structure due;to the vortex lattice effect. The orientation of the star coincides with the experimental data of scanning tunneling microscopy. That is, the r ay of the star extends toward the nearest-neighbor (next-nearest-neigh bor) vortex direction at higher (lower) energy.