Direct observation of ferroelectric polarization-modulated band bending at oxide interfaces

This study presents a direct visualization of the influences of ferroelectric polarization on the electronic properties of the Schottky contact at the Nb-SrTiO3/BiFeO3 hetero-interface using scanning tunneling microscopy and spectroscopy (STM/S). The evolution of the local density of states across the Nb-SrTiO3/BiFeO3 interface reveals the interfacial band alignment and the characteristic quantities of the metal/ferroelectric contact. The unique combination of STM and STS in this study delivers an approach to obtain critical information on the interfacial electronic configurations of ferroelectric oxide interfaces and also their variation with ferroelectric polarization switching. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3691615]