BaCu, a Two-Dimensional Electride with Cu Anions.

The electron-rich characteristic and low work function endow electrides with excellent performance in (opto)electronics and catalytic applications; these two features are closely related to the structural topology, constituents, and valence electron concentration of electrides. However, the synthesized electrides, especially two-dimensional (2D) electrides, are limited to specific structural prototypes and anionic -block elements. Here we synthesize and identify a distinct 2D electride of BaCu with delocalized anionic electrons confined to the interlayer spaces of the BaCu framework.

Stability and Semiconducting Behavior of Magnesium Polysulfides by Nonequivalent sp Hybridizations.

The Mg/S battery has attracted enormous interest in recent years due to its high theoretical capacity, low cost, and high security. However, the understanding of many intermediate magnesium polysulfides in the Mg/S battery remains elusive. Combining extensive structural search and first-principles calculations, we investigate the phase stability, structural character, and electronic structure of magnesium polysulfides in a wide range from MgS to MgS.

Potassium-activated anionic copper and covalent Cu-Cu bonding in compressed K-Cu compounds.

Elemental copper and potassium are immiscible under ambient conditions. It is known that pressure is a useful tool to promote the reaction between two different elements by modifying their electronic structure significantly. Here, we predict the formation of four K-Cu compounds (KCu, KCu, KCu, and KCu) under moderate pressure through unbiased structure search and first-principles calculations.

Pressure induced semiconductor-semimetal-superconductor transition of magnesium hexaborides.

A thorough structural exploration was performed for MgB combining the global structure searching method with first-principles calculations. Besides the known Cmcm phase, new phases, i.e.

Synergistic effects of reduced graphene oxide with freeze drying tuned interfacial structure on performance of transparent and flexible supercapacitors.

Transparent and flexible supercapacitors (TFSCs) could diversify the future wearable electronics owing to the fascinating optoelectronic and electrochemical performances. Herein, we report symmetric TFSCs assembled by reduced graphene oxide (rGO)@Ag nanowire/poly (ethylene terephthalate) (PET) transparent electrodes for capacitive storage, in which the interfacial structure of rGO film can be tuned by a facile freeze drying technique. The enlarged interlayer spacing of rGO film deteriorated the electronic migration derived from the loose layer structure, whereas about 33-52% of the areal capacitance of TFSCs was boosted as compared with the ones without freeze drying at the same transmittance.

Metal-to-Semiconductor Transition and Electronic Dimensionality Reduction of CaN Electride under Pressure.

The discovery of electrides, in particular, inorganic electrides where electrons substitute anions, has inspired striking interests in the systems that exhibit unusual electronic and catalytic properties. So far, however, the experimental studies of such systems are largely restricted to ambient conditions, unable to understand their interactions between electron localizations and geometrical modifications under external stimuli, e.g.

Structural Diversity and Electronic Properties of 3d Transition Metal Tetraphosphides, TMP (TM = V, Cr, Mn, and Fe).

Transition-metal (TM) phosphides attract increasing attention with applications for energy conversion and storage, due to their outstanding physical, chemical, and electronic properties. The 3d transition metal tetraphosphides (TMP, TM = V, Cr, Mn, and Fe) possess multiple allotropies and rich electronic properties. Here, we perform the investigations of the structural, electronic, and elastic properties for 3d-TMP (TM = V, Cr, Mn, and Fe) using density functional theory (DFT) calculations.

Coexistence of Superconductivity and Superhardness in Beryllium Hexaboride Driven by Inherent Multicenter Bonding.

Unique multicenter bonding in boron-rich materials leads to the formation of complex structures and intriguing properties. Here global structural searches are performed to unearth the structure of beryllium hexaboride (BeB) synthesized decades ago. Three BeB phases (α, β, and γ) were predicted to be stable at ambient and high pressures.

Diverse ruthenium nitrides stabilized under pressure: a theoretical prediction.

First-principles calculations were performed to understand the structural stability, synthesis routes, mechanical and electronic properties of diverse ruthenium nitrides. RuN with a new I-4m2 symmetry stabilized by pressure is found to be energetically preferred over the experimental NaCl-type and ZnS-type ones. The Pnnm-RuN2 is found to be stable above 1.

Structural variety beyond appearance: high-pressure phases of CrB4 in comparison with FeB4.

Employing particle swarm optimization (PSO) combined with first-principles calculations, we systemically studied high-pressure behaviors of hard CrB4. Our predictions reveal a distinct structural evolution under pressure for CrB4 despite having the same initial structure as FeB4. CrB4 is found to adopt a new P2/m structure above 196 GPa, another Pm structure at a pressure range of 261-294 GPa and then a Pmma structure beyond 294 GPa.