title: Probing local bias-induced transitions using photothermal excitation contact resonance atomic force microscopy and voltage spectroscopy.
abstract: Nanomechanical properties are closely related to the states of matter, including chemical composition, crystal structure, mesoscopic domain configuration, etc. Investigation of these properties at the nanoscale requires not only static imaging methods, e.g., contact resonance atomic force microscopy (CR-AFM), but also spectroscopic methods capable of revealing their dependence on various external stimuli. Here we demonstrate the voltage spectroscopy of CR-AFM, which was realized by combining photothermal excitation (as opposed to the conventional piezoacoustic excitation method) with the band excitation technique. We applied this spectroscopy to explore local bias-induced phenomena ranging from purely physical to surface electromechanical and electrochemical processes. Our measurements show that the changes in the surface properties associated with these bias-induced transitions can be accurately assessed in a fast and dynamic manner, using resonance frequency as a signature. With many of the advantages offered by photothermal excitation, contact resonance voltage spectroscopy not only is expected to find applications in a broader field of nanoscience but also will provide a basis for future development of other nanoscale elastic spectroscopies.
authors.affiliation: Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
authors.forename: Qian
authors.initials: Q
authors.lastname: Li
authors.forename: Stephen
authors.initials: S
authors.lastname: Jesse
authors.forename: Alexander
authors.initials: A
authors.lastname: Tselev
authors.forename: Liam
authors.initials: L
authors.lastname: Collins
authors.forename: Pu
authors.initials: P
authors.lastname: Yu
authors.forename: Ivan
authors.initials: I
authors.lastname: Kravchenko
authors.forename: Sergei V
authors.initials: SV
authors.lastname: Kalinin
authors.forename: Nina
authors.initials: N
authors.lastname: Balke
keywords: Young’s modulus; elastic spectroscopy; electrochemical reaction; ferroelectric; scanning probe microscopy