Decoupling of structural and electronic phase transitions in VO$_2$*

Using optical, TEM and ultrafast electron diffraction experiments we find that single crystal VO$_2$ microbeams gently placed on insulating substrates or metal grids exhibit different behaviors, with structural and metal-insulator transitions occuring at the same temperature for insulating substrates, while for metal substrates a {\it new monoclinic metal phase} lies between the insulating monoclinic phase and the metallic rutile phase. The structural and electronic phase transitions in these experiments are strongly first order and we discuss their origins in the context of current understanding of multi-orbital splitting, strong correlation effects and structural distortions that act cooperatively in this system.