Abstract
Quantum Spin Hall (QSH) has potential applications in low energy consuming spintronic devices and has become a researching hotspot recently. It benefits from insulators feature edge states, topologically protected from backscattering by time-reversal symmetry. The properties of methyl functionalized silicene (SiCH3) have been investigated using first-principles calculations, which show QSH effect under reasonable strain. The origin of the topological characteristic of SiCH3, is mainly associated with the s-pxy orbitals band inversion at Γ point, whilst the band gap appears under the effect of spin-orbital coupling (SOC). The QSH phase of SiCH3 is confirmed by the topological invariant Z2 = 1, as well as helical edge states. The SiCH3 supported by hexagonal boron nitride (BN) film makes it possible to observe its non-trivial topological phase experimentally, due to the weak interlayer interaction. The results of this work provide a new potential candidate for two-dimensional honeycomb lattice spintronic devices in spintronics.
Highlights
Two-dimensional (2D) topological insulators (TIs) or Quantum Spin Hall (QSH) insulators are characterized by insulating bulk and metallic edge states [1,2,3,4,5,6]
The opening gap and band inversion caused by the spin-orbital coupling (SOC) near the fermi level, means that there is a possibility of the QSH effect, which has gapless edge states protected by time-reversal symmetry (TRS)
It was found that the external strain can induce a topological phase transition in SiCH3 monolayer
Summary
Two-dimensional (2D) topological insulators (TIs) or Quantum Spin Hall (QSH) insulators are characterized by insulating bulk and metallic edge states [1,2,3,4,5,6]. The orbital filtering effect (OFE) can be applied to design a QSH insulator, which is an effective way to enhance the bulk band gap of 2D materials [26,27,28]. Based on first-principles calculations, we predicated a new QSH insulator in Si, by functionalized organic molecule group methyl. We found that the SiCH3 on BN film makes it possible to support the non-trivial topological phase, due to the weak interlayer interaction. These results may provide a new candidate for designing large-gap QSH insulators, which is necessary for device applications in spintronics
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
