First-principles calculation of electronic and structural properties of YBa2Cu3O6+y

The normal state of the prototypical high-T-c superconductor YBa2Cu3O6+y is described via advanced ab initio band-theory techniques suited for strongly correlated materials. We describe the system at generic oxygen doping y between the Mott-insulating limit (y=0) and the optimally doped Fermi liquid (y=1), exploring the metal-insulating transitions related to the paramagnetic-antiferromagnetic competition in the CuO2 planes, and to the order-disorder competition in the CuOy chains. Our study demonstrates the usefulness of ab initio calculations based on density-functional theory, when suitably adapted to strongly correlated systems, to describe doped cuprates.