Observation of Weyl fermions in a magnetic non-centrosymmetric crystal

• Published in: Nature communications Vol. 11; no. 1; pp. 3356 - 8
• Main Authors: Sanchez, Daniel S., Chang, Guoqing, Belopolski, Ilya, Lu, Hong, Yin, Jia-Xin, Alidoust, Nasser, Xu, Xitong, Cochran, Tyler A., Zhang, Xiao, Bian, Yi, Zhang, Songtian S., Liu, Yi-Yuan, Ma, Jie, Bian, Guang, Lin, Hsin, Xu, Su-Yang, Jia, Shuang, Hasan, M. Zahid
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 03-07-2020; Nature Publishing Group; Nature Portfolio
• Subjects: 639/301/1034; 639/766/119; Brillouin zones; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; condensed-matter physics; Curie temperature; Electric arcs; Elementary excitations; Fermions; Ferroelectricity; Humanities and Social Sciences; Magnetic properties; multidisciplinary; Photoelectric emission; Photoelectron spectroscopy; Science; Science (multidisciplinary); Second harmonic generation; Spectroscopic analysis; Spectroscopy; Spectrum analysis; Symmetry; theory and computation; Topology; Transport properties
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-020-16879-1

The absence of inversion symmetry in non-centrosymmetric materials has a fundamental role in the emergence of a vast number of fascinating phenomena, like ferroelectricity, second harmonic generation, and Weyl fermions. The removal of time-reversal symmetry in such systems further extends the variety of observable magneto-electric and topological effects. Here we report the striking topological properties in the non-centrosymmetric spin-orbit magnet PrAlGe by combining spectroscopy and transport measurements. By photoemission spectroscopy below the Curie temperature, we observe topological Fermi arcs that correspond to projected topological charges of ±1 in the surface Brillouin zone. In the bulk, we observe the linear energy-dispersion of the Weyl fermions. We further observe a large anomalous Hall response in our magneto-transport measurements, which is understood to arise from diverging bulk Berry curvature fields associated with the Weyl band structure. These results establish a novel Weyl semimetal phase in magnetic non-centrosymmetric PrAlGe.
The search for magnetic Weyl fermion remains a challenge. Here, the authors report angle-resolved photoemission spectroscopy and magnetotransport measurements resolving the topological properties of Weyl fermion quasiparticles in magnetic non-centrosymmetric crystal PrAlGe.