Transition from nodal loop to nodal chain phase in a periodically modulated optical lattice

TL;DR

This paper investigates how a tunable optical lattice system can transition between nodal loop and nodal chain phases, revealing a controllable topological phase change in a 2D system with artificial magnetic flux.

Contribution

It introduces a model for a tunable optical lattice that demonstrates a transition between nodal loop and nodal chain semimetals via modulation strength control.

Findings

The system can realize both nodal loop and nodal chain Fermi surfaces.

Transition between phases is achieved by tuning the modulation potential strength.

The model extends the understanding of topological phase transitions in optical lattices.

Abstract

We propose to study the transition from a nodal loop to nodal chain phase in a tunable two-dimensional $\pi$-flux lattice with periodical modulation potential. The Hamiltonian describes a periodically modulated optical lattice system under artificial magnetic fluxes and the tunable modulation phase factor provides additionally an artificial dimension of external parameter space. We demonstrate that this lattice system is able to describe a semimetal with either nodal loop or nodal chain Fermi surface in the extended three-dimensional Brillouin zone. By changing the strength of modulation potential $V$, we realize the transformation between the nodal-loop and nodal-chain semimetal.