title: Crossover between weak antilocalization and weak localization of bulk states in ultrathin Bi₂Se₃ films.
abstract: We report transport studies on the 5 nm thick Bi₂Se₃ topological insulator films which are grown via molecular beam epitaxy technique. The angle-resolved photoemission spectroscopy data show that the Fermi level of the system lies in the bulk conduction band above the Dirac point, suggesting important contribution of bulk states to the transport results. In particular, the crossover from weak antilocalization to weak localization in the bulk states is observed in the parallel magnetic field measurements up to 50 Tesla. The measured magneto-resistance exhibits interesting anisotropy with respect to the orientation of parallel magnetic field B// and the current I, signifying intrinsic spin-orbit coupling in the Bi₂Se₃ films. Our work directly shows the crossover of quantum interference effect in the bulk states from weak antilocalization to weak localization. It presents an important step toward a better understanding of the existing three-dimensional topological insulators and the potential applications of nano-scale topological insulator devices.
authors: 1] International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China [2] Collaborative Innovation Center of Quantum Matter, Beijing, People's Republic of China.
authors: Huichao
authors: H
authors: Wang
authors: 1] International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China [2] Collaborative Innovation Center of Quantum Matter, Beijing, People's Republic of China.
authors: Haiwen
authors: H
authors: Liu
authors: 1] State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, People's Republic of China [2] Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
authors: Cui-Zu
authors: CZ
authors: Chang
authors: Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China.
authors: Huakun
authors: H
authors: Zuo
authors: 1] International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China [2] Collaborative Innovation Center of Quantum Matter, Beijing, People's Republic of China.
authors: Yanfei
authors: Y
authors: Zhao
authors: 1] International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China [2] Collaborative Innovation Center of Quantum Matter, Beijing, People's Republic of China.
authors: Yi
authors: Y
authors: Sun
authors: Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China.
authors: Zhengcai
authors: Z
authors: Xia
authors: 1] Collaborative Innovation Center of Quantum Matter, Beijing, People's Republic of China [2] State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, People's Republic of China [3] Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
authors: Ke
authors: K
authors: He
authors: 1] Collaborative Innovation Center of Quantum Matter, Beijing, People's Republic of China [2] State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, People's Republic of China [3] Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
authors: Xucun
authors: X
authors: Ma
authors: 1] International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China [2] Collaborative Innovation Center of Quantum Matter, Beijing, People's Republic of China.
authors: X C
authors: XC
authors: Xie
authors: 1] Collaborative Innovation Center of Quantum Matter, Beijing, People's Republic of China [2] State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, People's Republic of China.
authors: Qi-Kun
authors: QK
authors: Xue
authors: 1] International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China [2] Collaborative Innovation Center of Quantum Matter, Beijing, People's Republic of China.
authors: Jian
authors: J
authors: Wang