Inducing a Lifshitz transition by extrinsic doping of surface bands in the topological crystalline insulator Pb1-xSnxSe.
The narrow gap semiconductor Pb1-xSnxSe was investigated for topologically protected surface states in its rocksalt structural phase for x=0.45, 0.23, 0.15, and 0. Angle-resolved photoelectron spectroscopy of intrinsically p-doped samples showed a clear indication of two Dirac cones, eccentric about the time-reversal invariant point X¯ of the surface Brillouin zone for all but the x=0 sample. Adsorption of alkalies gradually filled the surface bands with electrons, driving the x>0 topological crystalline insulator systems through Lifshitz transitions, and from a holelike to electronlike Fermi surface. The electron-doped bands in x>0 samples exhibited the full configuration of the Dirac cones, also confirming electron-hole symmetry of the surface bands.
Department of Physics, Princeton University, Princeton, New Jersey 08544, USA and Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
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Pletikosić
Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
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Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
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Valla