Holographic Fermionic Liquid with Lattices

We investigate the holographic fermions over a gravitational lattice background with a rather low temperature. Since the rotation symmetry is broken on the plane, the lattice effects change the shape of the Fermi surface within the first Brillouin zone from a circle to an ellipse. When the Fermi surface intersects with the Brillouin zone boundary, the band structure with a band gap is observed through a numerical analysis. We construct a lattice model sourced by a scalar field as well as an ionic lattice model without the scalar field. In both cases we find the similar physical results.