In the present work, we demonstrate that C-doped Zr5Pt3 is an electron–phonon superconductor (with critical temperature T C = 3.8 K) with a nonsymmorphic topological Dirac nodal-line semimetal state, which we report here for the first time. The superconducting properties of Zr5Pt3C0.5 have been investigated by means of magnetization, resistivity, specific heat, and muon spin rotation and relaxation (μSR) measurements. We find that at low temperatures, the depolarization rate is almost constant and it can be well described by a single-band s‐wave model with a superconducting gap of 2Δ(0)/k B T C = 3.84, somewhat higher than the value of BCS theory. From the transverse field μSR analysis, we estimate the London penetration depth λ L = 469 nm, superconducting carrier density n s = 1.83 × 1026 m−3, and effective mass m* = 1.428m e. The zero field μSR confirms the absence of any spontaneous magnetic field in the superconducting ground state. In order to gain additional insights into the electronic ground state of C-doped Zr5Pt3, we also performed first-principles calculations within the framework of density functional theory (DFT). The observed homogenous electronic character of the Fermi surface as well as the mutual decrease of T C and density of states at the Fermi level are consistent with the experimental findings of this study. However, the band structure reveals the presence of robust, gapless fourfold-degenerate nodal lines protected by 63 screw rotations and glide mirror planes. Therefore, Zr5Pt3 represents a novel, unprecedented condensed matter system to investigate the intricate interplay between superconductivity and topology.

In the present work, we investigate the electronic and elastic properties in equilibrium and under strain of the type-II Dirac semimetal NiTe 2 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.

The formation of two-dimensional oxide dodecagonal quasicrystals as well as related complex approximant phases were recently reported in thin films derived from BaTiO3 or SrTiO3 perovskites deposited on (111)-oriented Pt...

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Recently, the discovery of the quasiperiodic order in ultra-thin perovskite films reinvigorated the field of ultra-thin 2D oxide films on metals, and raised the question of the reasons behind the...

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MV 2 Ga 4 (M = Sc, Zr, Hf) compounds belong to an emerging class of materials showing a unique combination of unusual superconducting behavior with extended linear chains in the crystal structure. In order to gain insights into its mechanical and thermal properties, we have performed first-principles electronic-structure calculations in the framework of the Density Functional Theory (DFT). From the calculated second-order elastic constants, we have systematically shown that the extended linear vanadium chain substructures indeed give rise to an anisotropic regime in the elastic and mechanical moduli. The high density of valence and conduction electrons along the linear vanadium chains leads to a directional dependence of the reciprocal linear compressibility, Young's modulus and shear modulus. Poisson's ratio for several elongation directions is also drastically affected by the presence of extended V chains. If the elongation is along the V chains, all compounds exhibit practically the same Poisson ratio in directions perpendicular to it, further highlighting the importance of the V chains to the mechanical properties. Moreover, based on our results, we have discussed the possible consequences of the elastic anisotropy on the superconducting properties of the compounds. Finally, using the Debye-Grüneisen approximation, our calculations of thermal properties show a good agreement with the available experimental low temperature heat capacity data above the superconducting critical temperature.

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