AUTHOR=Gao Hongli , Meng Weizhen , Wang Lirong , Deng Jinxiang 

TITLE=Multiple-symmetry-protected lantern-like nodal walls in lithium-rich compound LiRuO2

JOURNAL=Frontiers in Physics

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2022.1081708

DOI=10.3389/fphy.2022.1081708

ISSN=2296-424X

ABSTRACT=<p>Topological semimetals have attracted wide attention due to their potential applications, such as electronic devices and electrocatalysis. Herein, based on the first-principles calculations and symmetry analysis, we first report that ternary compound <italic>pnnm</italic>-type LiRuO<sub>2</sub> is a typical lantern-like nodal wall semimetal. Specifically, without considering spin-orbit coupling (SOC), one-dimensional (1D) two-fold degenerate bands on the k<sub>i</sub> = ±π (i = x, y) planes form the two-dimensional (2D) topological state (namely, nodal surface) under the constraint of multiple symmetry operations. In addition, the symmetry-enforced nodal network is formed on the k<sub>z</sub> = ±π planes. Finally, these nodal networks and nodal surfaces are coupled together to form lantern-like nodal walls. Remarkably, these topological states are protected by multiple symmetries, namely, nonsymmorphic two-fold screw-rotational symmetry [<italic>S</italic><sub><italic>2i</italic></sub> (i = x, y)], time-reversal symmetry (<italic>T</italic>), inversion symmetry (<italic>I</italic>), glide plane symmetry (<italic>σ</italic><sub><italic>z</italic></sub>), and two-fold rotational symmetry (<italic>C</italic><sub><italic>2x/y</italic></sub>). In addition, we further discuss the effect of spin-orbit coupling on the lantern-like nodal walls. We find that even if LiRuO<sub>2</sub> contains <italic>S</italic><sub><italic>2z</italic></sub> and <italic>T</italic> symmetries, these nodal surfaces and nodal networks are still broken. Then, due to the existence of <italic>I</italic> and <italic>T</italic> symmetries, Dirac nodal lines and Dirac points are formed in the low-energy region. Therefore, our work indicates that LiRuO<sub>2</sub> is an excellent material platform for researching multiple topological states.</p>