Engineering of nested Fermi surface and transparent conducting p-type Delafossite CuAlO2: possible lattice instability or transparent superconductivity?

Based on ab initio electronic structure calculation using a super-cell FLAPW method, we propose a new valence control method for the fabrication of low-resistive p-type and transparent conducting oxides of Delafossite CuAlO2. We propose a Cu-vacancy doping method with decreasing the Cu-vapor pressure and with increasing the oxygen vapor pressure, or, Be- or Mg-acceptor doping method at the Al-site with decreasing the Al-vapor pressure and with increasing the Cu-vapor pressure. The heavily doped p-type CuAlO2 indicates the two-dimensional nested Fermi surfaces, which originate from the layered O–Cu–O dumbbell. Nested Fermi surfaces may cause possibly a lattice instability or a transparent superconductivity rather than magnetism.