Band Engineering of Dirac Semimetals using Charge Density Waves

TL;DR

This paper introduces a novel method using charge density waves and non-symmorphic symmetry to engineer ideal Dirac semimetals, demonstrated experimentally in GdSb$_{0.46}$Te$_{1.48}$, with implications for designing topological materials.

Contribution

The study proposes a new mechanism for designing topological Dirac semimetals using charge density waves and symmetry considerations, validated by experimental evidence.

Findings

GdSb$_{0.46}$Te$_{1.48}$ is a nearly ideal Dirac semimetal.

Most interfering bands at the Fermi level are suppressed.

Unusual transport behavior indicates localization of Dirac carriers.

Abstract

New developments in the field of topological matter are often driven by materials discovery, including novel topological insulators, Dirac semimetals and Weyl semimetals. In the last few years, large efforts have been performed to classify all known inorganic materials with respect to their topology. Unfortunately, a large number of topological materials suffer from non-ideal band structures. For example, topological bands are frequently convoluted with trivial ones, and band structure features of interest can appear far below the Fermi level. This leaves just a handful of materials that are intensively studied. Finding strategies to design new topological materials is a solution. Here we introduce a new mechanism that is based on charge density waves and non-symmorphic symmetry to design an idealized Dirac semimetal. We then show experimentally that the antiferromagnetic compound GdSb$_{0.46}$Te$_{1.48}$ is a nearly ideal Dirac semimetal based on the proposed mechanism, meaning that most interfering bands at the Fermi level are suppressed. Its highly unusual transport behavior points to a thus far unknown regime, in which Dirac carriers with Fermi energy very close to the node seem to gradually localize in the presence of lattice and magnetic disorder.