1211.1906 (Jun Xiong et al.)

Tuning the quantum oscillations of surface Dirac electrons in the
topological insulator Bi$_2$Te$_2$Se by liquid gating    [PDF]

Jun Xiong, Yuehaw Khoo, Shuang Jia, R. J. Cava, N. P. Ong

In Bi$_2$Te$_2$Se, the period of quantum oscillations arising from Dirac surface electrons can be increased 6-fold using ionic liquid gating. At large gate voltages, the Fermi energy reaches the $N$ = 1 Landau level in a 14-Tesla field. This enables the $\frac12$-shift predicted for the Dirac spectrum to be measured accurately. A surprising result is that liquid gating strongly enhances the surface mobility. By analyzing the Hall current, we show that the enhancement occurs on only one surface.

View original: http://arxiv.org/abs/1211.1906