Room-Temperature Ferromagnetism in Two-Dimensional Fe2Si Nanosheet with Enhanced Spin-Polarization Ratio

Searching experimental feasible two-dimensional (2D) ferromagnetic crystals with large spin-polarization ratio,. high Curie-temperature and. large-magnetic anisotropic energy is one key to develop next-generation spintronic nanodevices. Here) 2D Fe2Si nanosheet, one counterpart of Hapkeite mineral discovered in meteorite with novel magnetism is proposed on the basis of first-principles calculations.-The 2D Fe2Si Crystal has a slightly buckled triangular lattice with planar hexacoordinated Si and Fe atoms. The spin-polarized calculations with hybrid HSE06 function method indicate that 2D Fe2Si is a ferromagnetic half metal at its ground state with 100% spin-polarization ratio at Fermi energy level. The phonon spectrum calculation and ab initio molecular dynamic Simulation shows that 2D Fe2Si crystal has a high thermodynamic stability and its 2D lattice can be, retained at the temperature up to 1200 K. Monte Carlo simulations based on the Ising model,predict a Curie temperature over 780 K in 2D. Fe2Si crystal, which can be further tuned by applying a biaxial strain. Moreover, 2D structure and, strong in-plarre Fe Fe interaction endow Fe2Si nanosheet sizable magnetocrystalline anisotropy energy with,the-magnitude of at least two orders larger than those of Fe, Co and Ni bulks. These novel magnetic properties render the 2D Fe2Si crystal a very promising material for developing practical spintronic nanodevices