A new ternary pentagonal monolayer based on Bi with large intrinsic Dzyaloshinskii–Moriya interaction

Abstract

We systematically investigate the structural, electronic, and magnetic properties of a new pentagonal CoBiS monolayer using first-principles and Monte Carlo simulations. We find that Penta-CoBiS is stable mechanically, dynamically, and thermally and is an antiferromagnetic semiconductor with an indirect band gap of 0.5 eV with HSE functional. In addition, the band-gap increased by applying in-plane biaxial strain. We further show that this monolayer has an in-plane easy axis and possesses large intrinsic Dzyaloshinskii–Moriya interaction because of the broken inversion symmetry, and strong spin–orbit coupling originated from the Bi atoms. Moreover, the Néel temperature is also predicted using Monte Carlo simulations. An out-of-plane magnetic field B is then applied to compensate the in-plane anisotropy. It is found that for B = 1.72 T the spins are fully polarized to the out-of-plane direction. Our results demonstrate that Penta-CoBiS monolayer may find numerous applications in flexible spintronics and electronics.