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arXiv · 1806.01996

Optical Signatures of Dirac Nodal-lines in NbAs$_2$

Yinming Shao·Zhiyuan Sun·Ying Wang·Chenchao Xu·R. Sankar·Alex J. Breindel·Chao Cao·M. M. Fogler·Fangcheng Chou·Zhiqiang Li·T. Timusk·M. Brian Maple·D. N. Basov
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Abstract

Using polarized optical and magneto-optical spectroscopy, we have demonstrated universal aspects of electrodynamics associated with Dirac nodal-lines. We investigated anisotropic electrodynamics of NbAs$_2$ where the spin-orbit interaction triggers energy gaps along the nodal-lines, which manifest as sharp steps in the optical conductivity spectra. We show experimentally and theoretically that shifted 2D Dirac nodal-lines feature linear scaling $\sigma_1 (\omega)\sim\omega$, similar to 3D nodal-points. Massive Dirac nature of the nodal-lines are confirmed by magneto-optical data, which may also be indicative of theoretically predicted surface states. Optical data also offer a natural explanation for the giant magneto-resistance in NbAs$_2$.

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Yinming Shao, Zhiyuan Sun, Ying Wang, Chenchao Xu, R. Sankar, Alex J. Breindel, Chao Cao, M. M. Fogler, Fangcheng Chou, Zhiqiang Li, T. Timusk, M. Brian Maple, D. N. Basov. 2018-06-06. Optical Signatures of Dirac Nodal-lines in NbAs$_2$. https://doi.org/10.1073/pnas.1809631115

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