phase_change Piezoresponse single_layer FloppyDisk LMF Sapphire ScanningKelvinProbeMicroscopy ScanningThermalMicroscopy Defects Thermal Water Friction PFM ForceVolumeMapping TempControl Defect StainlessSteel MESA structure LiftHeight heterojunctions MetalCompound ThermalConductivity mechanical property Nickel MeltingPoint CrAu layers CntFilm SrO Worcester_Polytechnic_Institute Silver semifluorinated_alkane CrossSection HexagonalBoronNitride Titanate