We have studied transport and magnetic properties of Bi_{1-x}Sb_x, which is believed to be a topological insulator - a new state of matter where an insulating bulk supports an intrinsically metallic surface. In nominally insulating Bi_{0.91}Sb_{0.09} crystals, we observed strong quantum oscillations of the magnetization and the resistivity originating from a Fermi surface which has a clear two-dimensional character. In addition, a three-dimensional Fermi surface is found to coexist, which is possibly due to an unusual coupling of the bulk to the surface. This finding demonstrates that quantum oscillations can be a powerful tool to directly probe the novel electronic states in topological insulators.
@article{arxiv.0907.1125,
title = {Quantum oscillations in a topological insulator Bi_{1-x}Sb_{x}},
author = {A. A. Taskin and Yoichi Ando},
journal= {arXiv preprint arXiv:0907.1125},
year = {2015}
}