Direct observation of decoupled structural and electronic transitions and an ambient pressure monocliniclike metallic phase of VO2.

We report the simultaneous measurement of the structural and electronic components of the metal-insulator transition (MIT) of VO2 using electron and photoelectron spectroscopies and microscopies. We show that these evolve over different temperature scales, and are separated by an unusual monocliniclike metallic phase. Our results provide conclusive evidence that the new monocliniclike metallic phase, recently identified in high-pressure and nonequilibrium measurements, is accessible in the thermodynamic transition at ambient pressure, and we discuss the implications of these observations on the nature of the MIT in VO2.