Evidence for a magnetic-field induced ideal type-II Weyl state in antiferromagnetic topological insulator Mn(Bi1-xSbx)2Te4
cond-mat.mtrl-sci
/ Authors
Seng Huat Lee, David Graf, Yanglin Zhu, Hemian Yi, Samuel Ciocys, Eun Sang Choi, Rabindra Basnet, Arash Fereidouni, Aaron Wegner, Yi-Fan Zhao
and 11 more authors
Lujin Min, Katrina Verlinde, Jingyang He, Ronald Redwing, V. Gopalan, Hugh O. H. Churchill, Alessandra Lanzara, Nitin Samarth, Cui-Zu Chang, Jin Hu, Z. Q. Mao
/ Abstract
The discovery of Weyl semimetals (WSMs) has fueled tremendous interest in condensed matter physics. WSMs require breaking of either inversion symmetry (IS) or time-reversal symmetry (TRS); they can be categorized into type-I and type-II WSMs, characterized by un-tilted and strongly tilted Weyl cones respectively. Type-I WSMs with breaking of IS or TRS and type-II WSMs with IS breaking have been realized experimentally, but TRS-breaking type-II WSM still remains elusive. In this article, we report an ideal TRS-breaking type-II WSM with only one pair of Weyl nodes observed in the antiferromagnetic topological insulator Mn(Bi1-xSbx)2Te4 under magnetic fields. This state is manifested by a large intrinsic anomalous Hall effect, a non-trivial $\mathrm{π}$ Berry phase of the cyclotron orbit and a large positive magnetoresistance in the ferromagnetic phase at an optimal sample composition. Our results establish a promising platform for exploring the physics underlying the long-sought, ideal TRS breaking type-II WSM.