Computational materials design for superconductivity in hole-doped delafossite CuAlO2 : Transparent superconductors

We have calculated the superconducting critical temperature Tc of hole-doped delafossite CuAlO2 based on first-principles calculations. According our calculation, 0.2–0.3 hole-doped CuAlO2 can become a phonon-mediated high-Tc superconductor with Tc≃50K. In the hole-doped CuAlO2, the A1L1 phonon mode that stretches the O–Cu–O dumbbell has a strong interaction with electrons of the flat band in Cu 3d3z2−r2 and the O 2pz anti-bonding ππ-band.

► Calculations about superconducting critical temperature of hole-doped CuAlO2.
► Fermi level is on the anti-bonding band of Cu and O.
► Atomic oscillation of the A1L1 phonon mode is parallel to the covalent bond.
► A1L1 phonon mode has a strong electron–phonon interaction.
► Critical temperature of 0.3 hole-doped CuAlO2 is about 50 K.