Single-phase antiperovskite nitride GeNCo3 with space group Pm3̅m is successfully synthesized by a solid-gas reaction. The crystal structure, magnetism, specific heat at low temperatures, Hall effect, and electrical and thermal transport properties are widely investigated. Exhilaratingly, a canonical spin-glass (SG) behavior is observed in GeNCo3 with a freezing temperature T0 = 79.43 K, dynamical exponent zν = 6.156, and flipping time τ0 = 5.0 × 10(-12) s. The origin of the SG state in GeNCo3 is likely due to the atomic disorder introduced by the Ge vacancies. This is further proven by the measurements of Ge0.9NCo3 with more Ge deficiencies.
The structural, magnetic, electrical and thermal transport properties of the polycrystalline samples Ca 3 Co 4− x In x O 9 ( x = 0, 0.05, 0.10, 0.15, and 0.20) have been investigated systematically. The results indicate that the In‐substitution has a negative effect on the low‐temperature ferrimagnetic transition and the propagation of spin‐density‐wave. All In‐doped samples have a much larger resistivity than that of the un‐doped sample. And the temperature region where the Fermi liquid transport mechanism dominates is remarkably widened via In‐doping. However, for the In‐doped samples, as the In‐doped content increases, the value of resistivity ρ decreases monotonously and the electronic correlation in the system enhances. With the addition of In‐ions in Ca 3 Co 4 O 9 system, the thermopower S and the ZT value decrease. The results are suggested to originate from the variations of carrier concentration and lattice disharmony in this system induced by In‐doping.
A one-pot synthesis of a well-matched and high-stability 1T-M 0.71 W 0.29 S 2 /Ti 3 C 2 T x MXene heterostructure with high supercapacitor performance.
Detection and identification of molecular materials based on their THz frequency vibrational resonances remains an open technological challenge. The need for such technology is illustrated by its potential uses in explosives detection (e.g., RDX) or identification of large biomolecules based on their THz-frequency vibrational fingerprints. The prevailing approaches to THz sensing often rely on a form of waveguide spectroscopy, either utilizing geometric waveguides, such as metallic parallel plate, or plasmonic waveguides made of structured metallic surfaces with sub-wavelength corrugation. The sensitivity of waveguide-based sensing devices is derived from the long (1 cm or longer) propagation and interaction distance of the THz wave with the analyte. We have demonstrated that thin InSb layers with metallic gratings can support high quality factor "true" surface plasmon (SP) resonances that can be used for THz plasmonic sensing. We find two strong SP absorption resonances in normal-incidence transmission and investigate their dispersion relations, dependence on InSb thickness, and the spatial distribution of the electric field. The sensitivity of this approach relies on the frequency shift of the SP resonance when the dielectric function changes in the immediate vicinity of the sensor, in the region of deeply sub-wavelength thickness. Our computational modeling indicates that the sensor sensitivity can exceed 0.25 THz per refractive index unit. One of the SP resonances also exhibits a splitting when tuned in resonance with a vibrational mode of an analyte, which could lead to new sensing modalities for the detection of THz vibrational features of the analyte.
Herein, we have systematically reported the synthesis, structure, magnetism, and electrical/thermal transport properties of $\mathrm{AsNC}{\mathrm{r}}_{3}$. Tetragonal-antiperovskite metallic $\mathrm{AsNC}{\mathrm{r}}_{3}$ exhibits a second-order ferromagnetic (FM)-paramagnetic (PM) transition around 243 K, where the resistivity and specific heat also show a related change. Based on the obtained parameters from basic physical properties, the nature of weak electron-electron correlation was confirmed by both the Kadowaki-Woods ratio and Wilson ratio. Moreover, the value of the Rhodes-Wolfarth ratio (1.312) is larger than 1, suggesting an itinerant ferromagnetism in $\mathrm{AsNC}{\mathrm{r}}_{3}$. To further clarify the magnetic interaction of the $\mathrm{AsNC}{\mathrm{r}}_{3}$ system, the study of critical behavior around the FM-PM transition has been performed. The critical exponents ($\ensuremath{\beta}$, $\ensuremath{\gamma}$, and $\ensuremath{\delta}$) of $\mathrm{AsNC}{\mathrm{r}}_{3}$ obtained from different methods are very close to the theoretical values of the mean-field model ($\ensuremath{\beta}=0.5$, $\ensuremath{\gamma}=1.0$, and $\ensuremath{\delta}=3.0$), indicating the existence of a long-range FM interaction. Besides, the exchange interaction distance $J(r)\ensuremath{\sim}{r}^{\ensuremath{-}4.3}$ for $\mathrm{AsNC}{\mathrm{r}}_{3}$ decreases more slowly than that of mean-field model $J(r)\ensuremath{\sim}{r}^{\ensuremath{-}4.5}$, further confirming the long-range magnetic coupling in our system. The strong hybridization between Cr-$3d$ and N-$2p$ states as well as between Cr-$3d$ and As-$4p$ states confirmed by our theoretical calculations results in the itinerant characterization of carriers and the long-range FM interaction in tetragonal-antiperovskite $\mathrm{AsNC}{\mathrm{r}}_{3}$.
In this work, we report a simple and effective method for enhancing the photonic spin Hall effect (SHE) via singularity induced by destructive interference in an ultrathin uniaxial slab. Deriving from anisotropy, the incident angles corresponding to destructive interference for p - and s -polarized waves will be deviated, leading to an enhancement peak in transverse spin shift. Interestingly, by adjusting the thickness of slab, the destructive interference and the Brewster effect can act together. At this point, the photonic SHE exhibits great singularity, and the maximum transverse spin shift can approach about three times more than that of the Brewster effect acting alone. This Letter reveals the influence of the interference effect on photonic SHE in layered media and provides a simple way to achieve enhanced photonic SHE.
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