Topological edge states induced by the Zak phase in A3Bmonolayers,
Tomoaki Kameda, Feng Liu, Sudipta Dutta, and Katsunori Wakabayashi
Phys. Rev. B 99, 075426 (2019).
Published 19 February 2019
In crystalline systems, charge polarization is related to the Zak phase determined by bulk band topology. Nontrivial charge polarization induces robust edge states accompanied by fractional charge. In the Su-Schrieffer-Heeger model, it is known that the strong modulation of electron hopping causes nontrivial charge polarization even in the presence of inversion symmetry. Here, we consider a biatomic honeycomb lattice to introduce such strong modulation, i.e., a A3B sheet. By tuning the hopping ratio and on-site potential difference between the A and B atoms, we show that the topological phase transition characterized by the Zak phase occurs. Furthermore, we propose that C3N and BC3 are possible realistic materials on the basis of first-principles calculations. Both of them display topological edge states induced by the Zak phase without spin-orbital couplings and external fields, unlike conventional topological insulators.
Received 3 October 2018