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

We have calculated the superconducting critical temperature T c 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- T c superconductor with T c ≃ 50 K . 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 π -band.