Creation of the Dirac Nodal Line by Extrinsic Symmetry Engineering

Mingyang Tian; Jufeng Wang; Xiaofeng Liu; Weiwei Chen; Zhao Liu; Hongjian Du; Xiaochuan Ma; Xuefeng Cui; Aidi Zhao; Qinwei Shi; Zhengfei Wang; Yi Luo; Jinlong Yang; Bing Wang; J G Hou

doi:10.1021/acs.nanolett.0c00233

Creation of the Dirac Nodal Line by Extrinsic Symmetry Engineering

Nano Lett. 2020 Mar 11;20(3):2157-2162. doi: 10.1021/acs.nanolett.0c00233. Epub 2020 Feb 26.

Authors

Mingyang Tian^{1

2}, Jufeng Wang^{1

2}, Xiaofeng Liu^{1

2}, Weiwei Chen^{1

3}, Zhao Liu^{1

3}, Hongjian Du^{1

2}, Xiaochuan Ma^{1

2}, Xuefeng Cui^{1

2}, Aidi Zhao^{1

2}, Qinwei Shi^{1

2}, Zhengfei Wang^{1

3}, Yi Luo^{1

2}, Jinlong Yang^{1

2}, Bing Wang^{1

2

3}, J G Hou^{1

2}

Affiliations

¹ Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China.
² Synergetic Innovation Center of Quantum Information & Quantum Physics (CAS), University of Science and Technology of China, Hefei, Anhui 230026, China.
³ Key Laboratory of Strong-Coupled Quantum Matter Physics (CAS), University of Science and Technology of China, Hefei, Anhui 230026, China.

PMID: 32083884
DOI: 10.1021/acs.nanolett.0c00233

Abstract

The formation of the Dirac nodal line (DNL) requires intrinsic symmetry that can protect the degeneracy of continuous Dirac points in momentum space. Here, as an alternative approach, we propose an extrinsic symmetry protected DNL. On the basis of symmetry analysis and numerical calculations, we establish a general principle to design the nonsymmorphic symmetry protected 4-fold degenerate DNL against spin-orbit coupling in the nanopatterned 2D electron gas. Furthermore, on the basis of experimental measurements, we demonstrate the approximate realization of our proposal in the Bi/Cu(111) system, in which a highly dispersive DNL is observed at the boundary of the Brillouin zone. We envision that the extrinsic symmetry engineering will greatly enhance the ability for artificially constructing the exotic topological bands in the future.

Keywords: Dirac nodal line; band engineering; extrinsic symmetry; nonsymmorphic symmetry.