WS2 CompactDisk lithography phase_change chemical_compound Subhajjit FrictionalForceMicroscopy HardDiskMedia medical ConductingPolymer STM Reduction Trench Composite Growing Insulator domain_switching PUR Imprint vertical_PFM Treatment LithiumNiobate UnivMaryland polyvinyl acetate FloppyDisk PrCurve Ferrite AM-KPFM Thermoplastic_polyurethane PinpointNanomechanicalMode Nanostructure FM_SKPM Varistor Chromium Oxide