Heavy electrons at metallic Fermi surfaces, a superlattice property

The near-E(F) electronic structure and Fermi surface of Cu/Co superlattices are investigated by a tight-binding model and the Green function matching method. The more striking feature is the development of extremely dispersionless bands. Variation of the Cu and Co slab thicknesses changes the superlattice bands' energy. For periodic values of the Co thickness, Cu/Co superlattices exhibit a one-particle flat band at the Fermi level. As a consequence, a significant region of the superlattice Fermi surface has three-dimensional character.