ARE HIGH-TC SUPERCONDUCTORS LUTTINGER OR FERMI LIQUIDS

We use the Fermi liquid picture to discuss the normal state behaviour of fermions confined to a single CuO2 layer. Particles are described with the help of the five-states model (one d state, two bonding and two nonbonding p states). It is found that two distinct types of quasi-particles can coexist at the Fermi surface, namely (i), less correlated fermions which originate from holes in the nonbonding p orbitals and (ii), holes in bonding p orbitals which form Kondo-like singlets with holes on copper sites. © 1990, Elsevier Science Publishers B.V. (North-Holland). All rights reserved.