Worcester_Polytechnic_Institute amplitude_modulation UnivCollegeLondon Barium_titanate Ptfe Pore Switching alkanes Indent STM PFM Crystal Domain I-VSpectroscopy VerticalPFM Aluminum Materials Mapping OpticalModulator pulsed_laser_deposition HfO2 BCZT Varistor SKKU atomic_steps MechanicalProperty LiftHeight ito_film Grain Corrosion NTU LDPE Sperm Graphene PinpointPFM