Effect of conductive atomic force microscope tip loading force on tip-sample interface electronic characteristics: Unipolar to bipolar resistive switching transition

This study shows that tip loading force in conductive atomic force microscope (CAFM) is an important parameter determining electronic properties of tip-sample interface. At higher tip loading force, electrochemical breakdown of moisture layer and redox reactions cause changeover from unipolar to bipolar switching in Pt tip-Cu2O junction. Change in forming voltage due to tip force (and thus contact area) is opposite to that observed in micro range due to electric field enhancement effect. Results of the present study are important in studying filamentary conduction, nanometric mapping of charge carriers at the interface of complex oxide heterostructures, and other studies by CAFM.