Topological Raman Band in Carbon Nanohorn

TL;DR

This paper theoretically demonstrates that the topology of carbon nanohorns induces a unique $D$ Raman band in Raman spectroscopy, distinguishable from the ordinary $D$ band, via the Aharonov-Bohm effect.

Contribution

It introduces the concept of topology-induced Raman features in carbon nanohorns and predicts a new topological $D$ band observable in Raman spectra.

Findings

Topology induces a distinct $D$ Raman band in carbon nanohorns.

The topological $D$ band is distinguishable by its peak position.

A non-zero winding number activates the topological $D$ band.

Abstract

Raman spectroscopy has been used in chemistry and physics to investigate the fundamental process involving light and phonons (quantum of lattice vibration). The carbon nanohorn introduces a new subject to Raman spectroscopy, namely topology. We show theoretically that a photo-excited carrier with a non-zero winding number activates a topological $D$ Raman band through the Aharonov-Bohm effect. The topology-induced $D$ Raman band can be distinguished from the ordinary $D$ Raman band for a graphene edge by its peak position.