Assessment of interstitial potentials for rapid prediction of absolute band energies in crystals

Electronic band alignment is a demanding process for first-principles simulations, but an important factor in materials selection for applications including electrocatalysis and photoelectrochemistry. Here, we revisit a bulk alignment procedure, originally developed by Frensley and Kroemer, using modern computational tools. The electrostatic potential in the interstitial region, obtained from density functional theory, with four exchange correlation functionals, is used to predict the valence band offsets of 27 zinc blende semiconductors. The results are found to be in qualitative agreement with Frensley and Kroemer’s original data. In addition to absolute electron energies, the possibility of extracting effective ionic charges is investigated and compared to Bader partial charges. With further developments, such a procedure may support rapid screening of the bulk ionization potential and electron affinity of crystals, as we illustrate with an extension to rock salt and perovskite structure types.