Laha Antu, Yoshida Suguru, Marques Dos Santos Vieira Francisco, Yi Hemian, Lee Seng Huat, Ayyagari Sai Venkata Gayathri, Guan Yingdong, Min Lujin, Gonzalez Jimenez Jose, Miao Leixin, Graf David, Sarker Saugata, Xie Weiwei, Alem Nasim, Gopalan Venkatraman, Chang Cui-Zu, Dabo Ismaila, Mao Zhiqiang
Department of Physics, Pennsylvania State University, University Park, PA, USA.
2D Crystal Consortium, Materials Research Institute, Pennsylvania State University, University Park, PA, USA.
Nat Commun. 2024 Apr 26;15(1):3532. doi: 10.1038/s41467-024-47781-9.
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 (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 (BaSrCaEuYb)MnSb (denoted as AMnSb), giving access to a polar structure with a space group that is not present in any of the parent compounds. AMnSb is an entropy-stabilized phase that preserves its linear band dispersion despite considerable lattice disorder. Although both AMnSb and AMnSb have quasi-two-dimensional crystal structures, the two-dimensional Dirac states in the pristine AMnSb 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.
狄拉克半金属和外尔半金属是当代凝聚态物理的核心主题，发现具有狄拉克/外尔电子态的新化合物对于拓扑材料和量子技术的发展至关重要。在此，我们展示了一种广泛适用的策略，即利用高组态熵来设计相对论电子态。我们以AMnSb（A = Ba、Sr、Ca、Eu和Yb）狄拉克材料家族为例，证明在A位混合Ba、Sr、Ca、Eu和Yb会生成化合物（BaSrCaEuYb）MnSb（记为AMnSb），从而获得一种具有任何母体化合物中都不存在的空间群的极性结构。AMnSb是一种熵稳定相，尽管存在相当大的晶格无序，但其仍保留线性能带色散。尽管AMnSb和AMnSb都具有准二维晶体结构，但通过舒布尼科夫 - 德哈斯振荡测量揭示，原始AMnSb中的二维狄拉克态在高熵相中因局部结构畸变而演变成高度各向异性的准三维狄拉克态。
