Transient electron scavengers modulate carrier density at a polar/nonpolar perovskite oxide heterojunction

We show how transient electron scavengers can be utilized to control the carrier concentration at polar/nonpolar perovskite interfaces. By combining quantitative synchrotron x-ray-based interface structure determination with ab initio modeling, we demonstrate that Nd vacancy formation and the resulting formation of Nd adatoms, stabilized by oxygen scavengers at the growth front, can quantitatively account for the decreased carrier concentration at the SrTiO3/n NdTiO3/SrTiO3(001) heterojunction for n=1 unit cell. This study yields insight into growth mechanisms and the effect of transient species and defects on the electronic properties of oxide heterojunctions.