Polarity Control of Ferroelectric BiFeO$_{3}$/Metal Junctions for Switchable Diode and Photovoltaic Devices

Ferroelectric materials possess spontaneous polarization which can be used to control numerous functionalities of the materials by switching the polarization or modifying domain structure with an electric field. One of emerging phenomena in ferroelectrics is the control of charge transport by switching the polarization. Although charge conduction ($i.e.$, leakage current) in ferroelectrics has been considered as a detrimental factor to practical applications, an interaction between conduction and ferroelectric polarization has recently attracted much attention as a route for novel functionalities. In this presentation, we will report on the ferroelectric control of charge conduction in BiFeO$_{3}$/metal junctions: the BiFeO$_{3}$/metal interfaces can have either blocking or non-blocking contacts according to the polarization direction of the BiFeO$_{3}$ films, allowing non-volatile control of diode-like conduction characteristics. The resulting rectifying and photovoltaic effects can be turned on and off, as well as be flipped in polarity, depending on the ferroelectric domain structures.