Prediction of Quantum Anomalous Hall Insulator in Functionalized GaBi Honeycomb
Christian P. Crisostomo1*, Sung-Ping Chen1, Zhi-Quan Huang1, Chia-Hsiu Hsu1, Feng-Chuan Chuang1, Hsin Lin2,3, Arun Bansil4
1Department of Physics, National Sun Yat-Sen University, Kaohsiung, Taiwan
2Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, Singapore
3Department of Physics, National University of Singapore, Singapore, Singapore
4Department of Physics, Northeastern University, Boston, Massachusetts, USA
* presenting author:Christian Crisostomo,
Using first-principles electronic calculations, we predict functionalized GaBi honeycomb under tensile strain to harbor quantum anomalous hall (QAH) insulating phase. A single band inversion at Γ point was found in spin-polarized band structure of half-fluorinated planar strained GaBi. In order to confirm the topological properties, we evaluated the Chern number (C) and found that C = 1, indicating the presence of QAH phase. Additionally, the same value was also obtained by using hydrogen atoms, instead of fluorine atoms, as the adsorbate in both planar and buckled GaBi. Moreover, the electronic spectrum of a half-fluorinated GaBi nanoribbon with armchair or zigzag edges possess only one edge band crossing the Fermi level within the band gap. Finally, a suitable substrate which could induce the similar effect of half-hydrogenation or-fluorination on the GaBi honeycomb could be used for spintronic devices.

Keywords: Quantum Anomalous Hall Effect, First-principles Calculations, Topological Phase Transition, Electronic Structures