Common-Anion Rule and Its Limits - Photoemission-Studies of Cuinxga1-Xse2-Ge and Cuxag1-Xinse2-Ge Interfaces

Synchrotron-radiation photoemission data show that the valence-band discontinuities of CuIn x Ga1 − x Se2-Ge and Cu x Ag1 − x InSe2-Ge interfaces are independent of x within the experimental accuracy of 0.1 eV. We argue that this result is consistent with the Wei-Zunger explanation of the breakdown of the common-anion rule, which is based on a substantial role of the cation d states in determining the valence-band-edge position.