Estudo numérico dos invariantes topológicos em nanofitas de grafeno

Abstract

Topological insulators are an emerging class of electronic materials that have a bulk band gap, but have metallic states on their edge or surface. These metallic states are protected by symmetry, having potential applications in spintronic devices and quantum computation. The vast majority of topological compounds are 2D or 3D, with a very few examples of 1D materials, such as the Su-Schrieffer-Heeger (SSH) model, which describes the poly- acetylene molecule. However, polyacetylene is a very difficult material to work with and so far no experiments have been done using polyacetylene on spintronic devices. Recently, several studies have appeared for armchair graphene nanoribbons (AGNR) heterostructure, where one can observe the emergence of zero-energy topological states at the junction of nanoribbons with different topological phases, and some of these systems have already been synthesized and characterized. In this work, an analysis is made of the topological properties of nanoribbons characterized by the existence of a chiral symmetry where we calculate the topological invariant of several ribbons and verify the emergence of junction states between ribbons with different values of the appropriate topological invariant, the so-called winding number.