Effect of Mechanical Strain on the Optical Properties of Nodal-Line Semimetal ZrSiS

Abstract

Optical properties of nodal-line semimetal ZrSiS are studied using first-principles calculations. Frequency-independent optical conductivity is a fingerprint of the infrared optical response in ZrSiS. It is found that this characteristic feature is robust with respect to uniaxial compressive strain of up to 10 GPa, yet with the flat region being narrowed with increasing strain. Upon uniaxial tensile stress of 2 GPa, the Fermi surface undergoes a Lifshitz transition accompanied by a weakening of the interband screening, which reduces the spectral weight of infrared excitations. It is also shown that the high-energy region is characterized by low-loss plasma excitations at ≈20 eV with essentially anisotropic dispersion. Strongly anisotropic dielectric properties suggest the existence of a hyperbolic regime for plasmons in the deep ultraviolet range. Although the frequencies of high-energy plasmons are virtually unaffected by external uniaxial deformation, their dispersion can be effectively tuned by strain. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimNational Natural Science Foundation of China, NSFC: 117742692018FYA0305800S.Y. acknowledges financial support from the National Key R & D Program of China (Grant No. 2018FYA0305800) and National Science Foundation of China (Grant No. 11774269). A.N.R. acknowledges travel support from FLAG-ERA JTC2017 Project GRANSPORT. Numerical calculations presented in this paper were performed on a supercomputing system in the Supercomputing Center of Wuhan University

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