|DATE||July 12 (Thu), 2018|
|TITLE||Topological phases in graphene nanoribbon systems|
Recently it has been discovered that the electronic structures of semiconducting graphene nanoribbons (GNRs) can be classified into different topological phases depending on width, edge, and termination. I will introduce the symmetry protected topological phases in various geometries of GNRs of one-dimensional systems, and derive the topological invariants of GNRs with a Wannier function method and the tight-binding approach. The emergence of topological junction states will be confirmed in the GNR heterojunctions formed by the two topologically distinct GNR segments due to the bulk-boundary correspondence. In a finite GNR segment, topological end states develop at the nontrivial end which faces the vacuum. Our work is expected to provide new designs of novel GNR heterojunctions as well as future GNR-based nanoelectronic devices.