Signature of low-dimensional quasi-F centers in zirconium-rich electrides.

Electrides are a class of materials consisting of non-nuclear excess electrons as quasi-F centers or Farbe centers within a positively charged lattice framework, and have significant applications in the fields of electrochemistry, spintronics, and electrode materials. Using first-principles quantum mechanical calculations, we have demonstrated exotic electronic structures of zirconium-rich electrides, ZrX (X = O, Se, and Te), and obtained the quantitative values of charge transfer (oxidation states), and projected density of states associated with the localized quasi F-centers. The localized interstitial anionic electrons exhibit significant charge transfer values of approximately -1.

First-Principles Prediction of New 2D -SiPN: A Wide Bandgap Semiconductor.

Pentagonal two-dimensional ternary sheets are an emerging class of materials because of their novel characteristic and wide range of applications. In this work, we use first-principles density functional theory (DFT) calculations to identify a new pentagonal SiPN, -SiPN, which is geometrically, thermodynamically, dynamically, and mechanically stable, and has promising experimental potential. The new -SiPN shows an indirect bandgap semiconducting behavior that is highly tunable with applied equ-biaxial strain.

Large Negative Poisson's Ratio and Anisotropic Mechanics in New Penta-PBN Monolayer.

The scarce negative Poisson's ratio (NPR) in a two-dimensional (2D) material is an exceptional auxetic property that offers an opportunity to develop nanoscale futuristic multi-functional devices and has been drawing extensive research interest. Inspired by the buckled pentagonal iso-structures that often expose NPR, we employ state-of-the-art first-principles density functional theory calculations and analyses to predict a new 2D metallic ternary auxetic penta-phosphorus boron nitride (-PBN) with a high value of NPR. The new -PBN is stable structurally, mechanically, and dynamically and sustainable at room temperature, with experimental feasibility.