Hydrogen dynamics and metallic phase stabilization in VO2

Experimental doping of VO2 with hydrogen has been shown to trigger the semiconductor-to-metal phase transition below room temperature. Here, we report the results of density functional calculations showing that hydrogen-induced lattice distortion stabilizes the metallic phase. We also show that hydrogen diffuses preferentially along the rutile [001] direction whereby surface orientations can be tailored for optimal transport. Finally, we show that hydrogen doping is energetically favored, but there is a 1.6 eV barrier for dissociation of hydrogen molecules on a (100) monoclinic surface. These results give insight into the effect of hydrogen on the properties and phase transition of VO2.