Communications Physics 6 : 204 (2023)
Chiral and helical states in selective-area epitaxial heterostructure
Huimin Sun 1,2,3, Yu Huang1,2,3, Mengyun He1,2,3, Yu Fu1,2,3, Sikang Zheng4, Bin Zhang 4, Chen Wang 5 & Qing Lin He 1,2,3
1 International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China.
2 Collaborative Innovation Center of Quantum Matter, Beijing 100871, China.
3 Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, Beijing 100871, China.
4 Analytical and Testing Center, Chongqing University, Chongqing 401331, China.
5 Center for Joint Quantum Studies and Department of Physics, School of Science, Tianjin University, Tianjin 300350, China.
Email: physcwang@tju.edu.cn; qlhe@pku.edu.cn
Abstract
The quasi-1D chiral edge states in a quantum anomalous Hall insulator are dissipationless, while the 2D helical surface states in a topological insulator are insensitive to spin-independent scatterings due to the topological protection. Both serve as essential ingredients for topological electronics. Here, we integrate these states into a single device using selective area epitaxy based on the molecular beam epitaxy technique. The chiral edge state comes from the quantum anomalous Hall insulator Cr:(Bi,Sb)2Te3, while the helical surface state comes from the intrinsic topological insulator (Bi,Sb)2Te3 which only interfaces with a partial edge of the former, forming a selective-area heterostructure. At the heterointerface, the chiral state in Cr:(Bi,Sb)2Te3 is allowed to be scattered into (Bi,Sb)2Te3 so that the incoming current will be redistributed according to the coordination between the chirality and helicity. Our device enables the collaboration between chiral and helical states for low-dissipative transport with tunable current dimension.
