Journal of Materials Chemistry C | 2021
Hypercoordinate two-dimensional transition-metal borides for spintronics and catalyst applications
Abstract
Two-dimensional (2-D) magnetic materials are promising to be ideal platforms for constructing novel spintronic devices. Until to now, most 2-D magnetic materials have mainly been achieved by the exfoliation of magnetic bulks that greatly limits their high-quality mass productions. In this work, we predicted a hypercoordinate 2-D planar structure, transition metal borides MB9 (M= Mn, Cr, V, Ti; B= boron), whose magnetic properties could be tuned by changing the type of the transition metal through a set of structural searches combined with first-principles calculations. The synthesis of MB9 can be possibly achieved through chemical vapor deposition by combining transition-metal M atoms with novel 2-D planar boron sheet B9 on Ag (111) substrate. The structural stabilities of MB9 structures were proved by using a set of phonon dispersion, molecular dynamics, and elastic constant calculations. Most interestingly, MnB9 shows excellent magnetic properties because of its 100% spin polarization ratio at the Fermi level, high Curie temperature of 240 K, and robust perpendicular magnetic anisotropy energy of 180 \uf06deV per Mn atom, which can be a promising candidate for enabling ferromagnetic spintronics at the nanoscale. In addition, all MB9 structures show an excellent catalytic activity for hydrogen evolution reaction (HER) comparing with HER-inactive B9 because the adsorption of M atom induces a charge redistribution of boron sheet.