High-entropy engineering of the crystal and electronic structures in a Dirac material.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38670964.
- Also identified by DOI 10.1038/s41467-024-47781-9 and PMC identifier 11053097.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Dirac and Weyl semimetals are a central topic of contemporary condensed matter physics, and the discovery of new compounds with Dirac/Weyl electronic states is crucial to the advancement of topological materials and quantum technologies. Here we show a widely applicable strategy that uses high configuration entropy to engineer relativistic electronic states. We take the AMnSb<sub>2</sub> (A = Ba, Sr, Ca, Eu, and Yb) Dirac material family as an example and demonstrate that mixing of Ba, Sr, Ca, Eu and Yb at the A site generates the compound (Ba<sub>0.38</sub>Sr<sub>0.14</sub>Ca<sub>0.16</sub>Eu<sub>0.16</sub>Yb<sub>0.16</sub>)MnSb<sub>2</sub> (denoted as A<sup>5</sup>MnSb<sub>2</sub>), giving access to a polar structure with a space group that is not present in any of the parent compounds. A<sup>5</sup>MnSb<sub>2</sub> is an entropy-stabilized phase that preserves its linear band dispersion despite considerable lattice disorder. Although both A<sup>5</sup>MnSb<sub>2</sub> and AMnSb<sub>2</sub> have quasi-two-dimensional crystal structures, the two-dimensional Dirac states in the pristine AMnSb<sub>2</sub> evolve into a highly anisotropic quasi-three-dimensional Dirac state triggered by local structure distortions in the high-entropy phase, which is revealed by Shubnikov-de Haas oscillations measurements.