High Curie-temperature ferromagnetism engineering in WTe2 monolayer: The case of Mn and Fe codoping with nonmetal-enhanced magnetic properties

Abstract

Searching for new two-dimensional (2D) ferromagnetic materials with high Curie temperature has attracted great research attention because of the rapid development of spintronics. In this work, efficient routes for the ferromagnetism engineering in WTe₂ monolayer are proposed. Pristine WTe₂ monolayer is intrinsically nonmagnetic, possessing a direct band gap of 1.07 eV. The monolayer is magnetized by separately doping with Mn and Fe transition metals with total magnetic moments of 1.00 and 0.94 ${\mu }_B$, respectively. Mn doping leads to the in-plane magnetic anisotropy (IMA), while the perpendicular magnetic anisotropy (PMA) is obtained by Fe doping. The ferromagnetic (FM) state is predicted to be stable in WTe₂ monolayer codoped with Mn and Fe atoms with a high Curie temperature of 644 K. In this case, the PMA with feature-rich magnetic semiconductor nature is found, which suggest the promise of MnFe-codoped system toward fabrication of magnetoresistive random access memories (MRAMs). Further, additional substitutional doping of nonmetal (NM = S, Se, Cl, and Br) atoms is proposed to alter the magnetic properties. It is found that S and Se impurities increase Curie temperature to very high values of 1261 and 743 K, respectively. Meanwhile, this parameter decreases to 522 and 496 K by Cl and Br dopant atoms, respectively. Herein, all NM impurities induce the PMA-to-IMA switching, where the IMA is stronger with halogen impurities. Such that MnFe+NM-codoped systems can be considered as 2D potential candidates for magnetic field sensing. Moreover, NM impurities also enhance the magnetic nature semiconductor by increasing the spin-up energy gap. Finally, the stability analysis suggests the feasible experimental realization and structural stability of all the doped/codoped WTe₂ systems. Our findings may recommend efficient routes to functionalize WTe₂ monolayer toward selective spintronic applications controlled by nonmetal atoms.