High-mobility Bi2Se3 nanoplates manifesting quantum oscillations of surface states in the sidewalls.
Magnetotransport measurements of topological insulators are very important to reveal the exotic topological surface states for spintronic applications. However, the novel properties related to the surface Dirac fermions are usually accompanied by a large linear magnetoresistance under perpendicular magnetic field, which makes the identification of the surface states obscure. Here, we report prominent Shubnikov-de Haas (SdH) oscillations under an in-plane magnetic field, which are identified to originate from the surface states in the sidewalls of topological insulator Bi2Se3 nanoplates. Importantly, the SdH oscillations appear with a dramatically weakened magnetoresistance background, offering an easy path to probe the surface states directly when the coexistence of surface states and bulk conduction is inevitable. Moreover, under a perpendicular magnetic field, the oscillations in Hall conductivity have peak-to-valley amplitudes of 2 e(2)/h, giving confidence to achieve a quantum Hall effect in this system. A cross-section view of the nanoplate shows that the sidewall is (015) facet dominant and therefore forms a 58° angle with regard to the top/bottom surface instead of being perpendicular; this gives credit to the surface states' behavior as two-dimensional transport.
1] State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University, Beijing 100871, P.R. China [2].
Yuan
Y
Yan
1] State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University, Beijing 100871, P.R. China [2].
Li-Xian
LX
Wang
1] EMAT (Electron Microscopy for Materials Science), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium [2].
Xiaoxing
X
Ke
EMAT (Electron Microscopy for Materials Science), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium.
Gustaaf
G
Van Tendeloo
1] State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University, Beijing 100871, P.R. China [2] Collaborative Innovation Center of Quantum Matter, Beijing, P.R. China.
Xiao-Song
XS
Wu
1] State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University, Beijing 100871, P.R. China [2] Collaborative Innovation Center of Quantum Matter, Beijing, P.R. China.
Da-Peng
DP
Yu
1] State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University, Beijing 100871, P.R. China [2] Collaborative Innovation Center of Quantum Matter, Beijing, P.R. China.
Zhi-Min
ZM
Liao