High-entropy engineering of the crystal and electronic structures in a Dirac material
Antu Laha, Suguru Yoshida, Francisco Marques dos Santos Vieira, Hemian Yi, Seng Huat Lee, Sai Venkata Gayathri Ayyagari, Yingdong Guan, Lujin Min, J. Jimenez, Leixin Miao, David Graf, Saugata Sarker, Weiwei Xie, Nasim Alem, Venkatraman Gopalan, Cui‐Zu Chang, Ismaïla Dabo, Zhiqiang Mao
Abstract
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 A MnSb 2 ( 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 0.38 Sr 0.14 Ca 0.16 Eu 0.16 Yb 0.16 )MnSb 2 (denoted as A 5 MnSb 2 ), giving access to a polar structure with a space group that is not present in any of the parent compounds. A 5 MnSb 2 is an entropy-stabilized phase that preserves its linear band dispersion despite considerable lattice disorder. Although both A 5 MnSb 2 and A MnSb 2 have quasi-two-dimensional crystal structures, the two-dimensional Dirac states in the pristine A MnSb 2 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.