A Class of topological nodal rings and its realization in carbon networks

TL;DR

This paper classifies topological nodal rings in carbon networks into three types based on energy dispersion slopes, explores their phase transitions under strain, and discusses their unique electronic properties and potential transport phenomena.

Contribution

It introduces a comprehensive classification of topological nodal rings in carbon networks and demonstrates their phase transitions and electronic characteristics under strain.

Findings

All three types of nodal rings can exist in carbon networks.

Strain induces phase transitions from topological metal to semiconductor.

Nodal rings exhibit diverse electron-hole pockets and Landau levels.

Abstract

Topological nodal rings can be classified into three types according to the slopes in their energy dispersion. The first two are made of type-I and II nodal points, respectively, while the third is made of both. In carbon networks, all three types can exist. Under strain, phase transitions from a topological metal to a semiconductor, take place, and at the transition points, these nodal rings shrink into type-I, II, and III semi-Dirac points. These topological features exhibit diverse electron-hole pocket patterns and Landau levels, which give rise to exotic transport properties.