Dember effect induced photovoltage in perovskite \textit{p}-\textit{n} heterojunctions

An unusual and rather large transient lateral photovoltage (LPV) has been observed in La$_{0.9}$Sr$_{0.1}$MnO$_{3}$/SrNb$_{0.01}$Ti$_{0.99}$O$_{3}$ and La$_{0.7}$Sr$_{0.3}$MnO$_{3}$/Si heterojunctions under the nonuniform irradiation of pulsed laser. The irreversible LPVs on both sides of a $p-n $ junction challenge the well established model for LPV in conventional semiconductor $p-n$ junctions, which can be well explained by Dember effect. Much larger LPV is observed in La$_{0.7}$Sr$_{0.3}$MnO$_{3}$/Si than that in La$_{0.9}$Sr$_{0.1}$MnO$_{3}$/SrNb$_{0.01}$Ti$_{0.99}$O$_{3}$. Similar results measured from both substrates of SrNb$_{0.01}$Ti$_{0.99}$O$_{3}$ and Si also support such a Dember effect. Much larger LPVs in heterojunctions than those in simple samples (SrNb$_{0.01}$Ti$_{0.99}$O$_{3}$ or Si) suggest a potential application of Dember effect in heterostructures.