Unconventional symmetry of vortex core in Abrikosov lattice for systems with anisotropic Fermi surface

We present microscopic calculations of fourfold-shaped Abrikosov vortices arising in a square crystal lattice. By solving the Bogoliubov–de Gennes equations, we demonstrate that as the Fermi surface is tuned from circular to square-like via the chemical potential, the Caroli–de Gennes–Matricon vortex-core states evolve from radially symmetric profiles into a pronounced fourfold-shaped pattern. We additionally reveal a simultaneous presence of C₄ symmetry from the Fermi surface and C₆ symmetry from the Abrikosov lattice. As a result, we anticipate unconventional symmetry features in the spatial pattern of zero-bias conductance in materials with anisotropic Fermi surfaces.C