Investigation of Local Ferroelectric Properties of Ultrathin Ferroelectric Films with Scanning Tunneling Microscopy

Scanning tunneling microscopy in ultrahigh vacuum conditions was used to study local ferroelectric properties of ultrathin ferroelectric BaTiO
3
film in SrTiO
3
/La
0.7
Sr
0.3
MnO
3
/BaTiO
3
structure. Interestingly, polarization state of the BaTiO
3
film could strongly influence the results of STM topographic images. It was found that the polarization induced changes in the local tunnel electroresistance could be used to study the local ferroelectric property distribution in thin ferroelectric film. Additionally, we develop an approach ensuring successful implementation of local ferroelectric property measurements with scanning tunneling microscopy technique.