Floquet-Weyl semimetals generated by an optically resonant interband transition

作     者：Runnan Zhang Ken-ichi Hino Nobuya Maeshima 

作者机构：Doctoral Program in Materials Science Graduate School of Pure and Applied Sciences University of Tsukuba Tsukuba Ibaraki 305-8573 Japan Division of Materials Science Faculty of Pure and Applied Sciences University of Tsukuba Tsukuba 305-8573 Japan Center for Computational Sciences University of Tsukuba Tsukuba 305-8577 Japan 

出 版 物：《Physical Review B》 (Phys. Rev. B)

年 卷 期：2022年第106卷第8期

页      面：085206-085206页

核心收录：

基　　金：Fundação para a Ciência e a Tecnologia, FCT, (PTDC/CCI-BIO/29266/2017) Japan Society for the Promotion of Science, KAKEN, (JP19K03695) 

主　　题：Optical pumping Topological materials Weyl semimetal 

摘      要：Floquet-Weyl semimetals (FWSMs) generated by irradiation of a continuous-wave laser with left-hand circular polarization (rotating in counterclockwise sense with time) on the group II–V narrow-gap semiconductor Zn3As2 are theoretically investigated, where the frequency of the laser is set nearly resonant with the band gap of the crystal. It is found that the excitation of the crystal by such a laser induces two types of FWSM phases that differ absolutely in character. To be specific, the associated two pairs of Weyl points are stably formed by band touching between Floquet sidebands ascribable to a valence band labeled Jz=±3/2 and a conduction band labeled Jz=±1/2, where Jz represents the z component of total angular-momentum quantum number of the Γ point and a double sign corresponds. Here, one FWSM state composed of the up-spin Floquet sidebands relevant to Jz=3/2 and 1/2 shows almost quadratic band-touching in the vicinity of the associated pair of Weyl points, while the other FWSM state composed of the down-spin Floquet sidebands relevant to Jz=−3/2 and −1/2 shows linear band-touching. Furthermore, it is revealed that both up-spin and down-spin sidebands host nontrivial two-dimensional surface states that are pinned to the respective pairs of the Weyl points. Both surface states also show different energy dispersions and physical properties. A more detailed discussion is presented in the text on the origin of the above findings, the chirality of the FWSM phases, the alteration of topological order, laser-induced magnetic properties, and so on.