A Comparative Study of Bandwidths in Copper Delafossites from X-ray Emission Spectroscopy

The widths of the valence bands in the copper (I) delafossites CuGaO2, CuInO2, and CuScO2 have been measured by O K-shell x-ray emission spectroscopy and are compared with previous experimental work on CuAlO2 and CuCrO2. In agreement with recent density-functional theory calculations it is found that the bandwidth decreases in the series CuAlO2 > CuGaO2 > CuInO2 > CuScO2. It is shown that states at the top of the valence band are of dominant Cu 3dz2 atomic character but with significant mixing with O 2p states.

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