title: Topological transport and atomic tunnelling-clustering dynamics for aged Cu-doped Bi2Te3 crystals.
abstract: Enhancing the transport contribution of surface states in topological insulators is vital if they are to be incorporated into practical devices. Such efforts have been limited by the defect behaviour of Bi2Te3 (Se3) topological materials, where the subtle bulk carrier from intrinsic defects is dominant over the surface electrons. Compensating such defect carriers is unexpectedly achieved in (Cu0.1Bi0.9)2Te3.06 crystals. Here we report the suppression of the bulk conductance of the material by four orders of magnitude by intense ageing. The weak antilocalization analysis, Shubnikov-de Haas oscillations and scanning tunnelling spectroscopy corroborate the transport of the topological surface states. Scanning tunnelling microscopy reveals that Cu atoms are initially inside the quintuple layers and migrate to the layer gaps to form Cu clusters during the ageing. In combination with first-principles calculations, an atomic tunnelling-clustering picture across a diffusion barrier of 0.57 eV is proposed.
authors.affiliation: National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and Department of Physics, Nanjing University, Nanjing 210093, China.
authors.forename: Taishi
authors.initials: T
authors.lastname: Chen
authors.affiliation: Department of Physics, Southeast University, Nanjing 211189, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Chen
authors.affiliation: Solid State Physics and Magnetism Section, KU Leuven, Leuven BE-3001, Belgium.
authors.forename: Koen
authors.initials: K
authors.lastname: Schouteden
authors.affiliation: National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and Department of Physics, Nanjing University, Nanjing 210093, China.
authors.forename: Wenkai
authors.initials: W
authors.lastname: Huang
authors.affiliation: School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China.
authors.forename: Xuefeng
authors.initials: X
authors.lastname: Wang
authors.affiliation: Solid State Physics and Magnetism Section, KU Leuven, Leuven BE-3001, Belgium.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Li
authors.affiliation: National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and Department of Physics, Nanjing University, Nanjing 210093, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Miao
authors.affiliation: School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China.
authors.forename: Xinran
authors.initials: X
authors.lastname: Wang
authors.affiliation: National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and Department of Physics, Nanjing University, Nanjing 210093, China.
authors.forename: Zhaoguo
authors.initials: Z
authors.lastname: Li
authors.affiliation: National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and Department of Physics, Nanjing University, Nanjing 210093, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Zhao
authors.affiliation: National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and Department of Physics, Nanjing University, Nanjing 210093, China.
authors.forename: Shaochun
authors.initials: S
authors.lastname: Li
authors.affiliation: National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and Department of Physics, Nanjing University, Nanjing 210093, China.
authors.forename: Fengqi
authors.initials: F
authors.lastname: Song
authors.affiliation: Department of Physics, Southeast University, Nanjing 211189, China.
authors.forename: Jinlan
authors.initials: J
authors.lastname: Wang
authors.affiliation: National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and Department of Physics, Nanjing University, Nanjing 210093, China.
authors.forename: Baigeng
authors.initials: B
authors.lastname: Wang
authors.affiliation: Solid State Physics and Magnetism Section, KU Leuven, Leuven BE-3001, Belgium.
authors.forename: Chris
authors.initials: C
authors.lastname: Van Haesendonck
authors.affiliation: National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and Department of Physics, Nanjing University, Nanjing 210093, China.
authors.forename: Guanghou
authors.initials: G
authors.lastname: Wang