2018/06/12 by Yinming Shao, Zhiyuan Sun, Ying Wang +10 · 1 citation
Physics and Astronomy · #cond-mat.mtrl-sci #cond-mat.mes-hall #physics.optics
paper · pdf · doi:10.1073/pnas.1809631115
published as PNAS Jan 2019, 116 (4) 1168-1173
arxiv created 2018/06/12 · arxiv updated 2019/01/24
Using polarized optical and magneto-optical spectroscopy, we have demonstrated universal aspects of electrodynamics associated with Dirac nodal-lines. We investigated anisotropic electrodynamics of NbAs2 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 σ1 (ω)∼ω, 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 NbAs2.