Superconductivity in dense scandium-based phosphides

Hardness and superconductivity in tetragonal LiB4 and NaB4

Boron-based compounds have triggered substantial attention due to their multifunctional properties, incorporating excellent hardness and superconductivity. While tetragonal metal borides LiB4 and NaB4 with BaAl4-type structure and striking clathrate boron motif have been induced under compression, there is still a lack of deep understanding of their potential properties at ambient pressure. We herein conduct a comprehensive study on I4/mmm-structured LiB4 and NaB4 under ambient pressure via first-principles calculations. Remarkably, both LiB4 and NaB4 are found to possess high Vickers hardness of 39 GPa, which is ascribed to the robust boron framework with strong covalency. Furthermore, their high hardness values together with distinguished stability make them highly potential superhard materials. Meanwhile, electron–phonon coupling analysis reveals that both LiB4 and NaB4 are conventional phonon-mediated superconductors, with critical temperatures of 6 and 8 K at 1 atmosphere pressure (atm), respectively, mainly arising from the coupling of B 2p electronic states and the low-frequency phonon modes associated with Li-, Na-, and B-derived vibrations. This work provides valuable insights into the mechanical and superconducting behaviors of metal borides and will boost further studies of emergent borides with multiple functionalities.

Coexistence of superconductivity and electride states in Ca2H with an antifluorite-type motif under compression

An unprecedented hydride Ca2H with an antifluorite-type structure is predicted to possess the coexistence of electride states and superconductivity under pressure. This study paves the way for the search of novel electride superconductor hydrides.

Enhanced ultrathin ultraviolet detector based on a diamond metasurface and aluminum reflector

Metasurface is a kind of sub-wavelength artificial electromagnetic structure, which can resonate with the electric field and magnetic field of the incident light, promote the interaction between light and matter, and has great application value and potential in the fields of sensing, imaging, and photoelectric detection. Most of the metasurface-enhanced ultraviolet detectors reported so far are metal metasurfaces, which have serious ohmic losses, and studies on the use of all-dielectric metasurface-enhanced ultraviolet detectors are rare. The multilayer structure of the diamond metasurface-gallium oxide active layer-silica insulating layer-aluminum reflective layer was theoretically designed and numerically simulated. In the case of gallium oxide thickness of 20 nm, the absorption rate of more than 95% at the working wavelength of 200-220 nm is realized, and the working wavelength can be adjusted by changing the structural parameters. The proposed structure has the characteristics of polarization insensitivity and incidence angle insensitivity. This work has great potential in the fields of ultraviolet detection, imaging, and communications.

Pressure-Driven Ne-Bearing Polynitrides with Ultrahigh Energy Density

Neon (Ne) can reveal the evolution of planets, and nitrogen (N) is the most abundant element in the Earth’s atmosphere. Considering the inertness of neon, whether nitrogen and neon can react has aroused great interest in condensed matter physics and space science. Here, we identify three new Ne–N compounds (i.e., NeN6, NeN10, and NeN22) under pressure by first-principles calculations. We find that inserting Ne into N2 substantially decreases the polymeric pressure of the nitrogen and promotes the formation of abundant polynitrogen structures. Especially, NeN22 acquires a duplex host-guest structure, in which guest atoms (Ne and N2 dimers) are trapped inside the crystalline host N20 cages. Importantly, both NeN10 and NeN22 not only are dynamically and mechanically stable but also have a high thermal stability up to 500 K under ambient pressure. Moreover, ultra-high energy densities are obtained in NeN10 (11.1 kJ/g), NeN22 (11.5 kJ/g), tetragonal t-N22 (11.6 kJ/g), and t-N20 (12.0 kJ/g) produced from NeN22, which are more than twice the value of trinitrotoluene (TNT). Meanwhile, their explosive performance is superior to that of TNT. Therefore, NeN10, NeN22, t-N22, and t-N20 are promising green high-energy-density materials. This work promotes the study of neon-nitrogen compounds with superior properties and potential applications.

Broadband metamaterial absorber based on hybrid multi-mode resonance in mid-wave and long-wave infrared region

Crystalline aluminum silicides with electride state and superconductivity under high pressure

Crystal structures and superconductivity of lithium and fluorine implanted gold hydrides under high pressures

The introduction of Li and F into a Au–H system induces the formation of unprecedented solid metallic Li–Au–H and nonmetallic F–Au–H compounds under compression, where Au–H bonds and superconductivity are discovered in some Li–Au–H compounds.

Multi-mode plasmonic resonance broadband LWIR metamaterial absorber based on lossy metal ring

Broadband perfect infrared wave absorption of unpolarized light over a wide range of angles in an ultrathin film is critical for applications such as thermal emitters and imaging. Although many efforts have been made in infrared broadband absorption, it is still challenging to cover the perfect absorption of broadband in the long-wave infrared band. We propose a long-wave infrared broadband, polarization, and incident angle insensitivity metamaterial absorber based on the supercell with four rings of two sizes. Broadband absorption covering the long-wave infrared band is realized by combining four PSPRs and LSPRs absorption peaks excited by the supercell structure. The absorptivity of our absorber exceeds 90% in the wavelength range of 7.76∼14µm, and the average absorptivity reaches 93.8%. The absorber maintains more than 80% absorptivity as the incident angle of unpolarized light reaches 60°, which may have promising applications for thermal emitters, infrared imaging, thermal detection.

Fabrication of Alkali Metal Boride: Honeycomb‐Like Structured NaB ₄ with High Hardness and Excellent Electrical Conductivity

Emerging Yttrium Phosphides with Tetrahedron Phosphorus and Superconductivity under High Pressures

Pressure-stabilized GdN6 with an armchair–antiarmchair structure as a high energy density material

Pressure-induced GdN6 with armchair–antiarmchair polynitrogen has a high energy density of 1.62 kJ g−1, with excellent explosive performance comparable to that of TNT, becoming the first high energy density material among lanthanide nitrides.

Superconductive Sodium Carbides with Pentagon Carbon at High Pressures

Unconventional Stable Stoichiometry of Vanadium Peroxide

Peroxides have attracted considerable attention due to their intriguing electronic properties and diverse applications. However, only a few transition metal peroxides have been known thus far, limiting the variety of...

Superconducting boron allotropes

Achieving high hydrogen evolution reaction activity of a Mo2C monolayer

Two-dimensional Mo2C materials (1T and 2H phases) have emerged as promising electrocatalysts for the hydrogen evolution reaction (HER) due to their low cost, inherent metallicity, and high stability.

High-Temperature Ferromagnetism in an Fe3P Monolayer with a Large Magnetic Anisotropy

Structural and electronic properties of tungsten oxides under high pressures

Predicted Pressure-Induced Superconducting Transition in Electride Li6P

Unveiling the Role of Oxygen Vacancy in Li2MnO3 upon Delithiation

Metallic P3C monolayer as anode for sodium-ion batteries

Sodium-ion batteries (SIBs) have become one of the most promising energy storage devices due to the high abundance and safety of sodium.

Two-Dimensional PC6 with Direct Band Gap and Anisotropic Carrier Mobility

Structural and Superconducting Properties of Tungsten Hydrides Under High Pressure

Gold with +4 and +6 Oxidation States in AuF4 and AuF6

Nonmetallic FeH6 under High Pressure

Hexagonal BC2N with Remarkably High Hardness

Pressure-Induced Stable Beryllium Peroxide

Pressure-induced stable BeN 4 as a high-energy density material

Stable and metallic two-dimensional TaC2as an anode material for lithium-ion battery

Two dimensional TaC2is a promising anode material from the standpoint of a high specific capacity, fast Li diffusion rate, low operating voltage, and good electronic conductivity.

Understanding the role of lithium sulfide clusters in lithium–sulfur batteries

Our results represent a significant step towards understanding the structures and stabilities of lithium sulfide clusters, and improving the performance of Li–S batteries.

Tetragonal Structure BC4 as a Superhard Material

Tellurium Hydrides at High Pressures: High-Temperature Superconductors

Silicon Framework-Based Lithium Silicides at High Pressures

Globally stable structures of LixZn (x = 1–4) compounds at high pressures

The convex hull diagram of LixZn (x= 1–4) and LiZn in thePm3̄mstructure at 100 GPa.

First-principle optimal local pseudopotentials construction via optimized effective potential method

ATLAS: A real-space finite-difference implementation of orbital-free density functional theory

Exploring the metallic phase of N2O under high pressure

Using the CALYPSO method, we proposed a new metallic structure of N2O under high pressure.

Crystal Structures and Electronic Properties of Cesium Xenides at High Pressures

Hypervalent Iodine with Linear Chain at High Pressure

Ten-fold coordinated polymorph and metallization of TiO2under high pressure

A stable and metallic CaC2-type structure of TiO2is identified with the highest coordination number among the known phases.

Pressure-induced structural changes and elemental dissociation of cadmium and mercury chalcogenides

The high-pressure structures and phase-transition sequences of the cadmium and mercury chalcogenides were unambiguously determined. An intriguing dissociation into Cd (or Hg) + X under strong compression was observed.

Phase Diagram and High-Temperature Superconductivity of Compressed Selenium Hydrides

Exploring High-Pressure Structures of N2CO