Abstract
Formation energies of native defects in Bi(TeSe), with comparison to ideal BiTeS, are calculated in density-functional theory to assess transport properties. BiSe is found to be type for both Bi- and Se-rich growth conditions, while BiTe changes from to type going from Te- to Bi-rich conditions, as observed. BiTeSe and BiTeS are generally type, explaining observed heavily doped -type behavior in most samples. A (0/−) transition level at 16 meV above valence-band maximum for Bi on Te antisites in BiTeSe is related to the observed thermally active transport gap causing a -to- transition at low temperature. Bi(TeSe) with are predicted to have high bulk resistivity due to effective carrier compensation when approaching the -to- crossover. Predicted behaviors are confirmed from characterization of our grown single crystals.
- Received 23 April 2012
DOI:https://doi.org/10.1103/PhysRevB.87.125303
©2013 American Physical Society