Engineering topological phases with a three-dimensional nodal-loop semimetal

TL;DR

This paper demonstrates how a 3D nodal-loop semimetal can be engineered with various gap terms to realize multiple topological phases, providing a unified approach for designing novel topological materials and their surface states.

Contribution

The study introduces a method to engineer diverse topological phases from a 3D nodal-loop semimetal using gap terms, unifying the creation of topological surface states with tunable properties.

Findings

Realized chiral insulator, second-order topological insulator, and Weyl semimetal phases.

Engineered topological surface states inherit dispersion from gap terms.

Guided the search for new topological materials with tunable surface states.

Abstract

A three-dimensional (3D) nodal-loop semimetal phase is exploited to engineer a number of intriguing phases featuring different peculiar topological surface states. In particular, by introducing various two-dimensional gap terms to a 3D tight-binding model of a nodal-loop semimetal, we obtain a rich variety of topological phases of great interest to ongoing theoretical and experimental studies, including chiral insulator, degenerate-surface-loop insulator, second-order topological insulator, as well as Weyl semimetal with tunable Fermi arc profiles. The unique concept underlying our approach is to engineer topological surface states that inherit their dispersion relations from a gap term. The results provide one rather unified principle for the creation of novel topological phases and can guide the search for new topological materials. Two-terminal transport studies are also carried out to distinguish the engineered topological phases.