Tubular Fermi surfaces in transition metal superlattices

¹ Instituto de Ciencia de Materiales de Madrid Consejo Superior de Investigaciones Científicas, Cantoblanco, 28049-Madrid, Spain
² Departamento de Física Aplicada, Facultad de Ciencias Químicas, Universidad de Castilla-La Mancha, 45001 Toledo, Spain

Received: 5 September 1997
Accepted: 3 November 1997

Abstract

Calculations of the Fermi surfaces of Co/Ni (001) and (111) superlattices, based on a tight-binding model and on a Green function approach, reveal that superlattice Fermi surfaces have a tubular structure with a highly anisotropic cylindrical topology. The superlattice potential changes the cubic symmetry of Co and Ni and leads to undulating multisheeted cylindrical Fermi surfaces with marked two-dimensional character and strong nesting in both perpendicular and growth directions. The uncommon superlattice topology may result in unique properties. In particular, large anisotropic transport coefficients and electronic instabilities associated to coupled points on the Fermi surface are expected.