title: Strain-induced electrostatic enhancements of BiFeO3 nanowire loops.
abstract: Semiconductor nanowires (NWs), due to their intriguing structural and physical properties, offer tremendous potential for future technological applications. The existence of strain in NWs can greatly affect, for instance, their mechanical, electrical and optical properties. Here, we report an extraordinary electrostatic response of semiconductor BiFeO3 NW loops, based on Kelvin probe force microscopy (KPFM) and electrostatic force microscopy (EFM). A substantial ∼300 mV surface potential difference, accompanied by an ∼29% higher surface charge density, was found on the NW loop. We also found that the electrostatic enhancement is strongly related to the strain present at the curvature of the NW loops. We propose that the electric polarization coupled with mechanical strain (piezoelectric effect) or strain gradient (flexoelectricity) as possible reasons to account for our observation. These findings provide new insights into multiferroic based semiconductor NWs under external stimuli as well as significant inspiration towards strain sensors and electromechanical devices with multifunctional sensing abilities.
authors.affiliation: Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2V4, Canada. jun11@ualberta.ca thundat@ualberta.ca.
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2V4, Canada. jun11@ualberta.ca thundat@ualberta.ca.
authors.forename: Kovur
authors.initials: K
authors.lastname: Prashanthi
authors.affiliation: Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2V4, Canada. jun11@ualberta.ca thundat@ualberta.ca.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Li
authors.affiliation: Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2V4, Canada. jun11@ualberta.ca thundat@ualberta.ca.
authors.forename: Ryan T
authors.initials: RT
authors.lastname: McGee
authors.affiliation: Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2V4, Canada. jun11@ualberta.ca thundat@ualberta.ca and Materials Department, University of California, Santa Barbara, California 93106-5050, USA.
authors.forename: Kaveh
authors.initials: K
authors.lastname: Ahadi
authors.affiliation: Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2V4, Canada. jun11@ualberta.ca thundat@ualberta.ca.
authors.forename: Thomas
authors.initials: T
authors.lastname: Thundat