Terahertz transitions in finite carbon chains

TL;DR

This paper predicts a THz optical effect in finite topological systems, highlighting the role of edge states in linear atomic chains, with potential applications in nanophotonics.

Contribution

It introduces a tight-binding model to analyze optical selection rules in finite chains with topologically protected edge states, emphasizing their significance in THz transitions.

Findings

Edge states enable THz interband transitions in long molecules

Finite chains exhibit unique optical selection rules due to topological states

Results applicable to various topologically protected systems

Abstract

We predict an optical effect associated with systems which exhibit topologically protected states separated by a finite distance. We develop a tight-binding model to calculate the optical selection rules in linear chains of atoms of different lengths, and show the crucial importance of edge states. For long enough molecules the interband transitions involving these edge states are in the highly sought-after THz frequency range. Although we have specifically considered finite carbon chains terminated by gold nanoparticles, the main results of our work can be generalized to various systems which exhibit topologically protected states separated by a finite distance.