Control of light transmission and reflection through nanostructured materials has led to demonstration of metamaterial absorbers that have augmented the performance of energy harvesting applications of several optoelectronic and nanophotonic systems. Here, for the first time, a broadband plasmonic metamaterial absorber is fabricated using two-dimensional titanium carbide (Ti 3 C 2 T x ) MXene. Arrays of nanodisks made of Ti 3 C 2 T x exhibit strong localized surface plasmon resonances at near-infrared frequencies. By exploiting the scattering enhancement at the resonances and the optical losses inherent to Ti 3 C 2 T x MXene, high-efficiency absorption (∼90%) for a wide wavelength window of incident illumination (∼1.55 μm) has been achieved.

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Robust and high-temperature stable (refractory) transition metal nitrides are an emerging class of nanophotonic materials aimed at durable, bio-and CMOS-compatible plasmonic and metasurface applications. In this work, we experimentally demonstrate titanium nitride-and zirconium nitride-based phase manipulating optical metasurfaces that exhibit a photonic spin Hall effect. In the developed all-nitride system, metal nitrides are combined with dielectric nitrides such as aluminum nitride and silicon nitride to design a highly anisotropic, multilayer resonator geometry that supports gap plasmons and enables high power efficiency (∼40%) and broad bandwidth of operation in the near-infrared wavelength region. A one-dimensional phase gradient created by geometric rotations of the resonators leads to simultaneous, spatial separation of right and left circular polarization as well as different frequency components of the incident light. This work shows that transition metal nitrides can be successfully integrated into efficient metasurface building blocks for planar, rugged optical devices.

We analyze the evolution of the normal and superconducting electronic properties in epitaxial TiN films, characterized by high Ioffe-Regel parameter values, as a function of the film thickness. As the film thickness decreases, we observe an increase of the residual resistivity, which becomes dominated by diffusive surface scattering for d ≤ 20 nm. At the same time, a substantial thicknessdependent reduction of the superconducting critical temperature is observed compared to the bulk TiN value. In such a high quality material films, this effect can be explained by a weak magnetic disorder residing in the surface layer with a characteristic magnetic defect density of ∼ 10 12 cm −2 . Our results suggest that surface magnetic disorder is generally present in oxidized TiN films. arXiv:1903.05009v3 [cond-mat.mtrl-sci]