In the present work, we investigate the electronic and elastic properties in equilibrium and under strain of the type-II Dirac semimetal NiTe2 using density functional theory. Our results demonstrate the tunability of Dirac nodes' energy and momentum with strain and that it is possible to bring them closer to the Fermi level, while other metallic bands are suppressed. We also derive a minimal 4-band effective model for the Dirac cones, which accounts for the aforementioned strain effects by means of lattice regularization, providing an inexpensive way for further theoretical investigations and easy comparison with experiments. On an equal footing, we propose the static control of the electronic structure by intercalating alkali species into the van der Waals gap, resulting in the same effects obtained by strain engineering and removing the requirement of in situ strain. Finally, evaluating the wave-function's symmetry evolution as the lattice is deformed, we discuss possible consequences, such as Liftshitz transitions and the coexistence of type-I and type-II Dirac cones, thus motivating future investigations.

In this Rapid Communication, we have examined the superconducting ground state of the HfV2Ga4 compound using resistivity, magnetization, zero-field (ZF), and transverse-field (TF) muon-spin relaxation and rotation (μSR) measurements. Resistivity and magnetization unveil the onset of bulk superconductivity with TC∼3.9 K. TF-μSR measurements show the temperature dependence of the superfluid density, indicating, surprisingly, a nodal two-gap s+d-wave superconducting order parameter. In addition, the ZF muon relaxation rate increases with decreasing temperature below 4.6 K, suggesting the presence of weak spin fluctuations. These observations pointed to an unconventional multiband nature of the superconducting ground state. To better understand these findings, we carry out first-principles electronic-structure calculations, further highlighting multiple disconnected sheets with very different orbital weights and spin-orbit coupling composing the Fermi surface, bridging the way for a nodal multiband superconductivity scenario. In this vein, therefore, the HfV2Ga4 family stands out as an open avenue to novel unexplored unconventional superconducting compounds and an ideal playground to investigate the mechanisms behind such phenomena.