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Title: Two-band model interpretation of the p- to n-transition in ternary tetradymite topological insulators

The requirement for large bulk resistivity in topological insulators has led to the design of complex ternary and quaternary phases with balanced donor and acceptor levels. A common feature of the optimized phases is that they lie close to the p- to n-transition. The tetradymite Bi{sub 2}Te{sub 3−x}Se{sub x} system exhibits minimum bulk conductance at the ordered composition Bi{sub 2}Te{sub 2}Se. By combining local and integral measurements of the density of states, we find that the point of minimum electrical conductivity at x = 1.0 where carriers change from hole-like to electron-like is characterized by conductivity of the mixed type. Our experimental findings, which are interpreted within the framework of a two-band model for the different carrier types, indicate that the mixed state originates from different types of native defects that strongly compensate at the crossover point.
Authors:
; ;  [1] ; ;  [2] ; ;  [3] ;  [2] ;  [4]
  1. Department of Chemistry, Northwestern University, 2145 Sheridan Rd., Evanston, Illinois 60208 (United States)
  2. Department of Chemistry and Biochemistry, University of California – Los Angeles, 607 Charles E. Young Drive East, Los Angeles, California 90095 (United States)
  3. Department of Materials Science and Engineering, Northwestern University, 2145 Sheridan Rd., Evanston, Illinois 60208 (United States)
  4. (United States)
Publication Date:
OSTI Identifier:
22499272
Resource Type:
Journal Article
Resource Relation:
Journal Name: APL Materials; Journal Volume: 3; Journal Issue: 8; Other Information: (c) 2015 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; BISMUTH TELLURIDES; DEFECTS; DENSITY OF STATES; ELECTRIC CONDUCTIVITY; ELECTRONS; MIXED STATE; MIXED STATES