Figure 5
From: Semiconductor–metal transition in Bi2Se3 caused by impurity doping
Possible scenarios to increase the carrier density at the S-M transition. (a) The EF is pinned on the bottom of the BCB above Tcr. The BCB is indicated by the parabolic line in which blue states under the EF are occupied by the electrons. (b) The BCB is lowered owing to the expansion of the band width below Tcr. (c) The BCB is split owing to electron correlation below Tcr.
