[10p-S423-1~13] CS.7 Code-sharing Session of 7.4 & 9.5

△ [10p-S423-12] A Study of Two-dimensional Quantum Spin Hall Phase in the Honeycomb Nanoribbons Including Two Different Atoms

〇Ren Ito¹, Kenji Kondo¹ (1.Hokkaido Univ., Research Inst. for Electronic Science)

Keywords:Quantum Spin Hall Phase, Topological Insulators, Nanoribbons

Recently, topological insulators have attracted much attention all over the world. It originates from two-dimensional quantum spin Hall insulators. In 2005, Kane and Mele have first theoretically proposed that graphene including spin-orbit-interactions (SOI) shows the quantum spin Hall (QSH) phase. They have discovered that two-dimensional QSH phases have topologically protected edge states in graphene nanoribbons. Although their contributions to topological materials are greatly important, they have not mentioned differences of QSH phases between zigzag and armchair-type of nanoribbons. There are few papers considering this difference around the world. Therefore, we consider that it is important to compare the electronic band structures and electron densities of QSH phase between these two types of nanoribbons. In addition, we can extend the Kane-Mele model to consider the honeycomb nanoribbons which contains two different atoms. In this case, it is unclear how the QSH phase changes from the graphene case since there are few studies about this extension. Especially, the phase diagram of QSH phase is unclear. Therefore, in this study, we theoretically consider the QSH phase of honeycomb nanoribbons which contain two different atoms and compare the QSH phase between zigzag and armchair-types of edges of the nanoribbons.