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arXiv · 2208.05177

In-plane and out-of-plane optical response of the nodal-line semimetals ZrGeS and ZrGeSe

J. Ebad-Allah·S. Rojewski·Y. L. Zhu·Z. Q. Mao·C. A. Kuntscher
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Abstract

Polarization-dependent reflectivity measurements were carried out over a broad frequency range on single-crystalline ZrGeSe and ZrGeS compounds, which are closely related to the prototype nodal-line semimetal ZrSiS. These measurements revealed the strongly anisotropic character of both ZrGeSe and ZrGeS, with a reduced plasma frequency for the out-of-plane direction {\bf E}$\| c$ as compared to the in-plane direction {\bf E}$\| ab$. For {\bf E}$\| ab$ the optical conductivity spectrum consists of two Drude terms followed by a shoulder or plateau-like behavior and a distinct U shape at higher energies, while for {\bf E}$\| c$ one Drude term is followed by a peak-like behavior and the U shape of the profile is less developed. Under external pressure, two prominent excitations appear in the out-of-plane optical conductivity spectrum of ZrGeSe, whose frequency position and oscillator strength show a weak anomaly at $\sim$3~GPa. Overall, the pressure-induced changes in the profile of the {\bf E}$\| c$ conductivity spectrum are much enhanced above $\sim$3~GPa. We compare our results to those recently reported for ZrSiS in a quantitative manner.

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J. Ebad-Allah, S. Rojewski, Y. L. Zhu, Z. Q. Mao, C. A. Kuntscher. 2022-08-10. In-plane and out-of-plane optical response of the nodal-line semimetals ZrGeS and ZrGeSe. https://doi.org/10.1103/physrevb.106.075143

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