Square-root higher-order Weyl semimetals

Lingling Song; Huanhuan Yang; Yunshan Cao; Peng Yan

doi:10.1038/s41467-022-33306-9

Square-root higher-order Weyl semimetals

Nat Commun. 2022 Sep 24;13(1):5601. doi: 10.1038/s41467-022-33306-9.

Authors

Lingling Song¹, Huanhuan Yang¹, Yunshan Cao¹, Peng Yan²

Affiliations

¹ School of Electronic Science and Engineering and State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China.
² School of Electronic Science and Engineering and State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China. yan@uestc.edu.cn.

Abstract

The mathematical foundation of quantum mechanics is built on linear algebra, while the application of nonlinear operators can lead to outstanding discoveries under some circumstances, such as the prediction of positron, a direct outcome of the Dirac equation which stems from the square-root of the Klein-Gordon equation. In this article, we propose a model of square-root higher-order Weyl semimetal (SHOWS) by inheriting features from its parent Hamiltonians. It is found that the SHOWS hosts both "Fermi-arc" surface and hinge states that respectively connect the projection of the Weyl points on the side surface and arris. We theoretically construct and experimentally observe the exotic SHOWS state in three-dimensional (3D) stacked electric circuits with honeycomb-kagome hybridizations and double-helix interlayer couplings. Our results open the door for realizing the square-root topology in 3D solid-state platforms.

Abstract

Grants and funding