2014/01/31 by Miao Zhou, Wenmei Ming, Zheng Liu +3 · 2 citations
Materials Science · Physics and Astronomy · #Band gap #Chemical and Physical Properties of Materials #Fermi energy #Hamiltonian (control theory) #Quantum and electron transport phenomena #Quantum anomalous Hall effect #Quantum spin Hall effect #Scaling #Spintronics #Surface states #Topological Materials and Phenomena #Topological insulator #cond-mat.mes-hall #cond-mat.mtrl-sci
paper · pdf · doi:10.1038/srep07102
published as Sci. Rep. 4, 7102 (2014) · Total 23 pages, 5 figures. Supporting information with additional 5 figures also included
arxiv created 2014/11/19 · openalex publication_date 2014/11/19 · arxiv updated 2014/11/21 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
For potential applications in spintronics and quantum computing, it is desirable to place a quantum spin Hall insulator [i.e., a 2D topological insulator (TI)] on a substrate while maintaining a large energy gap. Here, we demonstrate a unique approach to create the large-gap 2D TI state on a semiconductor surface, based on first-principles calculations and effective Hamiltonian analysis. We show that when heavy elements with strong spin orbit coupling (SOC) such as Bi and Pb atoms are deposited on a patterned H-Si(111) surface into a hexagonal lattice, they exhibit a 2D TI state with a large energy gap of ≥ 0.5 eV. The TI state arises from an intriguing substrate orbital filtering effect that selects a suitable orbital composition around the Fermi level, so that the system can be matched onto a four-band effective model Hamiltonian. Furthermore, it is found that within this model, the SOC gap does not increase monotonically with the increasing strength of SOC. These interesting results may shed new light in future design and fabrication of large-gap topological quantum states.