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Our SdH data can only be fitted with a + I i /4 offset, which is consistent with a minimal-cross-section Fermi surface that encloses either a nodal line or a 3D Dirac point. References 1 Mikitik, G. P. & Sharlai, Y. V. Low-frequency quantum oscillations in LaRhIn5: Dirac point or nodal line? To recapitulate, three plausible models have been presented by us and Mikitik and Sharlai: (i) a nodal line with a minimal cross-section, (ii) a Dirac point with a maximal cross-section, and (iii) a Dirac point with a minimal cross-section. The weak angle dependence of the SdH oscillation frequency supports the model of a 3D Dirac point enclosed by an isotropic Fermi surface. [Extracted from the article]

The phase offset of quantum oscillations is commonly used to experimentally diagnose topologically nontrivial Fermi surfaces. This methodology, however, is inconclusive for spin-orbit-coupled metals where π-phase-shifts can also arise from non-topological origins. Here, we show that the linear dispersion in topological metals leads to a T2-temperature correction to the oscillation frequency that is absent for parabolic dispersions. We confirm this effect experimentally in the Dirac semi-metal Cd3As2 and the multiband Dirac metal LaRhIn5. Both materials match a tuning-parameter-free theoretical prediction, emphasizing their unified origin. For topologically trivial Bi2O2Se, no frequency shift associated to linear bands is observed as expected. However, the π-phase shift in Bi2O2Se would lead to a false positive in a Landau-fan plot analysis. Our frequency-focused methodology does not require any input from ab-initio calculations, and hence is promising for identifying correlated topological materials. A versatile methodology to detect topological quasiparticles by transport measurements remains an open problem. Here, the authors propose and experimentally observe the temperature dependence of the quantum oscillation frequency as a signature of non-trivial band topology. [ABSTRACT FROM AUTHOR]

Weyl semimetals (WSMs) hosting Weyl points (WPs) with different chiralities attract great interest as an object to study chirality-related physical properties, topological phase transitions, and topological superconductivity. Quantum oscillation measurements and theoretical calculations imply that the type-II WPs in NbIrTe4 are robust against the shift of chemical potential making it a good material for pressure studies on topological properties. Here we report the results of electrical transport property measurements and Raman spectroscopy studies under pressures up to 65.5 GPa accompanied by theoretical electronic structure calculations. Hall resistivity data reveal an electronic transition indicated by a change of the charge carrier from multiband character to hole-type at ~12 GPa, in agreement with the calculated Fermi surface. An onset of superconducting transition is observed at pressures above 39 GPa, with critical temperature increasing as pressure increases. Moreover, theoretical calculations indicate that WPs persist up to highly reduced unit cell volume (−17%), manifesting that NbIrTe4 is a candidate of topological superconductor. [ABSTRACT FROM AUTHOR]