Termination layer dependence of Schottky barrier height forLa0.6Sr0.4MnO3/Nb:SrTiO3heterojunctions

Abstract

We have investigated the interfacial termination layer dependence of the Schottky barrier height (SBH) for heterojunctions between polar ${\text{La}}_{0.6}{\text{Sr}}_{0.4}{\text{MnO}}_{3}$ (LSMO) and nonpolar Nb-doped ${\text{SrTiO}}_{3}$ (Nb:STO). The SBH for $\text{LSMO}/{\text{TiO}}_{2}\text{-Nb}:\text{STO}$ is higher than the SBH predicted from the Schottky-Mott rule by 0.5 eV, indicating the formation of an interface dipole. In contrast, for LSMO/SrO-Nb:STO, the SBH is lower than that predicted from the Schottky-Mott rule by 0.4 eV. These results indicate that a change in the polarity of the polar LSMO overlayers results in inversion of the direction of the interface dipole. The modulation of SBH depending on the interfacial termination layer is reasonably explained by interfacial electronic reconstruction to prevent polar divergence.