VO2: A Phase Change Material for Micromechanics

Micro- and nano-mechanical systems may take advantage from using materials having multiple functional characteristics. VO2 is a compound characterised by a solid state phase transition (SSPT) just above room temperature, consisting in a concurrent metal-insulator transition and a change of lattice symmetry and parameters. Here, the combination of non-linear electrical response and structural changes is employed to realise a novel high-frequency mechanical actuation scheme, showing direct conversion from DC voltage to mechanical excitation in the MHz range and selective activation of the different mechanical modes of a microstructure.