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arXiv · 2104.05521

Optical conductivity signatures of open Dirac nodal lines

D. Santos-Cottin·M. Casula·L. de' Medici·F. Le Mardelé·J. Wyzula·M. Orlita·Y. Klein·A. Gauzzi·A. Akrap·R. P. S. M Lobo
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Abstract

We investigate the optical conductivity and far-infrared magneto-optical response of BaNiS$_2$, a simple square-lattice semimetal characterized by Dirac nodal lines that disperse exclusively along the out-of-plane direction. With the magnetic field aligned along the nodal line the in-plane Landau level spectra show a nearly $\sqrt{B}$ behavior, the hallmark of a conical-band dispersion with a small spin-orbit coupling gap. The optical conductivity exhibits an unusual temperature-independent isosbestic line, ending at a Van Hove singularity. First-principles calculations unambiguously assign the isosbestic line to transitions across Dirac nodal states. Our work suggests a universal topology of the electronic structure of Dirac nodal lines.

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D. Santos-Cottin, M. Casula, L. de' Medici, F. Le Mardelé, J. Wyzula, M. Orlita, Y. Klein, A. Gauzzi, A. Akrap, R. P. S. M Lobo. 2021-04-12. Optical conductivity signatures of open Dirac nodal lines. https://doi.org/10.1103/physrevb.104.l201115

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