Interlocking nodal chains and their examples in carbon networks

TL;DR

This paper introduces a new topological phase called interlocking nodal chains in carbon networks, exploring their properties, phase transitions under strain, and potential for electronic and magnetic applications.

Contribution

It proposes the concept of interlocking nodal chains, models their formation, and demonstrates their realization and phase transitions in strained carbon networks.

Findings

Interlocking nodal chains are a new topological phase in semimetals.

Strain induces phase transitions from nodal rings to interlocking chains.

Surface states and Landau levels indicate rich electronic properties.

Abstract

Nodal chain is a typical topological phase in nodal line semimetals. Here, we propose a new topological phase -- interlocking nodal chains, in which two sets of nodal chains are interlocked each other. It includes one- (1D), two- (2D) and three-dimensional (3D) versions, which can be produced by a three-band model. The 2D and 3D interlocking nodal chains will evolve into some other phases, such as double concentric isolated (or intersecting) nodal rings, coexisting nodal chain and isolated (or intersecting) nodal rings. These phases exhibit diverse surface states and Landau levels, which implies that there are rich electronic and magnetic properties associating with them. Moreover, the 2D interlocking nodal chains and related phase transitions can be realized in a series of carbon networks under strain. Without strain, topological phase in the carbon structures is double concentric isolated nodal rings. A larger tensile strain leads to the phase transiting to an interlocking nodal chain, while the middle phase is a coexisting phase of a nodal chain and isolated nodal rings. In addition, stability and synthesis of the carbon networks are discussed.