The pressure induced metallization of monoclinic vanadium dioxide
In this study, the high pressure behavior of monoclinic vanadium dioxide (VO2 (M1) was revisited using infrared reflectivity (IR) spectroscopy, Raman spectroscopy and in situ synchrotron X ray diffraction (XRD) up to 64.7 GPa. Upon compression, VO2 (M1) follows the expected the structure transition sequence, M1 M'1 X, and we found that the structural transition from M'1 to X phase is completed at about 59 GPa. Moreover, our IR data demonstrated that the M'1 phase is a semiconductor within the pressure region of 11.4 43.2 GPa and became metallic with further compression, and that the X phase is metallic. Further analysis suggests that the pressure induced metallization (PIM) of the M'1 phase is associated with electron electron correlations, while the PIM from the M'1 to the X phases is relate to structural phase transitions. These results provide further insight into the PIM of VO2 (M1)