The common‐anion rule and the role of cation states: Binary versus ternary semiconductors

The failure of the common‐anion rule for heterojunction interfaces involving binary semiconductors has been demonstrated by many recent experiments. Wei and Zunger have explained this puzzling result in terms of a substantial role of the cation d states in determining the valence‐band edge position. The same approach predicts that the valence‐band edge position of certain ternary semiconductors and of their quaternary alloys depends weakly on the composition. We present synchrotron‐radiation photoemission tests of these predictions.