  We report density functional theory (DFT) band structure calculations on the
transparent conducting oxides CuAlO2, CuGaO2, CuInO2 and CuCrO2. The use of the
hybrid functional sX-LDA leads to considerably improved electronic properties
compared to standard local density approximation (LDA) and generalized gradient
approximation (GGA) approaches. We show that the resulting electronic band gaps
compare well with experimental values and previous quasiparticle calculations
and show the correct trends with respect to the atomic number of the cation
(Al, Ga, In). The resulting energetic depths of Cu d and O p levels and the
valence band widths are considerable improvements compared to LDA and GGA and
in good agreement with available x-ray photoelectron spectroscopy (XPS) data.
Lastly, we show the calculated imaginary part of the dielectric function for
all four systems.
