Gate-voltage control of chemical potential and weak antilocalization in Bi₂Se₃

Phys Rev Lett. 2010 Oct 22;105(17):176602. doi: 10.1103/PhysRevLett.105.176602. Epub 2010 Oct 19.


We report that Bi₂Se₃ thin films can be epitaxially grown on SrTiO₃ substrates, which allow for very large tunablity in carrier density with a back gate. The observed low field magnetoconductivity due to weak antilocalization (WAL) has a very weak gate-voltage dependence unless the electron density is reduced to very low values. Such a transition in WAL is correlated with unusual changes in longitudinal and Hall resistivities. Our results suggest a much suppressed bulk conductivity at large negative gate voltages and a possible role of surface states in the WAL phenomena.