The tractor beam effect could be from the black phosphorus impurities in the sample. That's ferromagnetic so you have two kinds of forces on the flake. Earlier

The tractor beam effect could be from the black phosphorus impurities in the sample. That's ferromagnetic so you have two kinds of forces on the flake. Earlier I joked to my friend that this Beijing expert doesn't understand what he was seeing and we shouldn't laugh at his predicament.. an x-ray of his sample probably showed that there wasn't a lot of lk99.