Floating up of the extended states of Landau levels in a two-dimensional electron gas in silicon mosfet's
Shashkin A. A., Kravchenko G.V., Dolgopolov V.T.
Phase diagram in Η, Nt plane for a 2D electron gas in Si MOSFET's has been studied. It has been found that transition into a low-electron-density insulating phase occurs only if all the extended states have passed, leaving Fermi sea, through the Fermi level. In contrast to the case of high magnetic fields when the extended states of each Landau level follow its centre, in weak magnetic fields they float up and finally combine all together when decreasing magnetic field.