PNNL

Abstract

We have measured soft x-ray resonant photoemission for the n-SrTiO3-?/i-Si(001) (??= ~0.0003) hybrid semiconductor heterojunction with the goal of probing occupied electronic states in the band gap near the surface. By utilizing both swept-energy, angle-integrated and fixed-energy, angle-resolved spectroscopies, we identify the atomic and orbital character of the in-gap state as well as the different electronic phases that contribute to it. Specifically, we isolate the state associated with trapped charge on the n-SrTiO3-? surface due to surface depletion from the weakly localized gap state resulting from electronic correlation effects in the complex oxide.