Institute of Physics, Chinese Academy of Sciences, Beijing, China.
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.
我们报告说，Bi₂Se₃ 薄膜可以在 SrTiO₃ 衬底上外延生长，这使得通过背栅可以非常大程度地调节载流子密度。观察到的由于弱反局域（WAL）引起的低场磁导率对栅极电压的依赖性非常弱，除非电子密度降低到非常低的值。WAL 的这种转变与纵向和 Hall 电阻率的异常变化相关。我们的结果表明，在大的负栅极电压下，体电导率大大降低，并且表面态可能在 WAL 现象中起作用。
