Quasiparticle Spectrum of Vortices in Cuprates

The quasiparticle excitation spectrum of an isolated vortex in a clean layered d-wave superconductor is calculated, using both the Bogoliubov--de Gennes and the quasiclassical Eilenberger equations. Analytical solutions are obtained within the model of step-variation of the gap function, adjusting the Caroli, de Gennes and Matricon approach for low-lying excitations in cuprates. A large peak in the density of states in the "pancake" vortex core is found, caused by the two-dimensional and strong coupling nature of high-temperature superconductivity.