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. We find that this characteristic feature is robust with respect to external pressure of up to 10 GPa, yet with the flat region being narrowed with increasing pressure. Upon tensile stress of 2 GPa, the Fermi surface undergoes a topological transition accompanied by a weakening of the interband screening, which reduces the spectral weight of infrared excitations. We also show that the highenergy 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 pressure, their dispersion can be effectively tuned by strain.

Pressure-induced excitations in the out-of-plane optical response of the nodal-line semimetal ZrSiS

“…For both directions, σ 1 consists of a Drude term at low energies due to itinerant charge carriers. From the spectral weight analysis of the Drude contribution we obtain a plasma frequency ω p of 3.17 eV for E ab and 1.08 eV for E c, in agreement with the results of first-principles calculations [20]. The ratio of dc conductivities σ ab /σ c amounts to ∼16, which lies in between the values 8 and 30 given in Refs.…”

NMR determination of Van Hove singularity and Lifshitz transitions in nodal-line semimetal ZrSiTe

“…The sharp VHS adjacent to the protected nodal line implies that additional electronic features relying upon the enhanced g(E) could be engineered into this system [26][27][28][29][30], by tuning E F to the VHS. Tuning could be accomplished by chemical pressure [43], physical pressure or strain [16,44], and light activation [17] with the re-quired energy difference being quite small. This could be another avenue for switching the topological behavior for quantum computing applications.…”

NMR determination of Van Hove singularity and Lifshitz transitions in the nodal-line semimetal ZrSiTe

“…The sharp VHS adjacent to the protected nodal line implies that additional electronic features relying upon the enhanced g(E ) could be engineered into this system [26][27][28][29][30], by tuning E F to the VHS. Tuning could be accomplished by chemical pressure [43], physical pressure or strain [16,44], and light activation [17] with the required energy difference being quite small. This could be another avenue for switching the topological behavior for quantum computing applications.…”