Band-gap discontinuity in semiconductor alloys with dissimilar wavefunction characters at the band edges

The authors clarify here the cause behind the discontinuous bandgap behavior in certain isovalent alloys by studying $\ensuremath{\alpha}$-(Rh,Ga)${}_{2}$O${}_{3}$ alloys using first-principles calculations. This challenges the applicability of conventional empirical continuous rules. They demonstrate that this unusual behavior is due to the unconventional evolution of the wavefunction character at the band edges. This work emphasizes the importance of considering specific band-edge wavefunction character differences in endpoint materials for more accurate predictions of semiconductor alloy properties, which will help in designing better materials for electronics and optoelectronics.