A novel approach for nanoscale imaging and characterization of the
orientation dependence of electromechanical properties—vector
piezoresponse force microscopy (Vector PFM)—is described. The
relationship between local electromechanical response, polarization,
piezoelectric constants, and crystallographic orientation is analyzed in
detail. The image formation mechanism in vector PFM is discussed.
Conditions for complete three-dimensional (3D) reconstruction of the
electromechanical response vector and evaluation of the piezoelectric
constants from PFM data are set forth. The developed approach can be
applied to crystallographic orientation imaging in piezoelectric materials
with a spatial resolution below 10 nm. Several approaches for data
representation in 2D-PFM and 3D-PFM are presented. The potential of vector
PFM for molecular orientation imaging in macroscopically disordered
piezoelectric polymers and biological systems is discussed.