Chemical Trend of Superconducting Transition Temperature in Hole-doped   CuBO$_2$, CuAlO$_2$, CuGaO$_2$ and CuInO$_2$
  We calculated the superconducting transition temperature $T_{\rm c}$ of hole-doped CuBO$_2$, CuAlO$_2$, CuGaO$_2$ and CuInO$_2$ using first-principles. The calculated $T_{\rm c}$ are about 50 K for CuAlO$_2$, 10 K for CuBO$_2$ and CuGaO$_2$ and 1 K for CuInO$_2$ at maximum in the optimum hole-doping concentration. The low $T_{\rm c}$ of CuInO$_2$ is attributed to the weak electron-phonon interaction caused by the low covalency and heavy atomic mass. 
Akitaka Nakanishi, Hiroshi Katayama-Yoshida
cond-mat.supr-con