Results .Crystal structure study . We have grown MoO 3 flakes in atmospheric conditions using a modified version of the hot plate-based physical vapor transport method described in ref.56. Briefly, a molybdenum foil was oxidized on a hotplate at 540?°C, then a silicon wafer was placed on top. At this temperature, the molybdenum oxide sublimes and re-crystallizes on the surface of the Si wafer, which is at a slightly lower temperature, forming MoO 3 flakes. Then, a Gel-Film (Gel-P...