Electronic band structure and magnetic properties of I vacancy and nonmetallic atoms doped single layer PbI2

Abstract

We systematically explore the influence of I vacancy and a series of substitutional nonmetallic atoms, including F, Cl, Br, Si, P and S, on the stability, geometric structure, electronic structure and magnetic properties of single layer PbI2 using first-principles calculations. The results show that I vacancy and nonmetallic atoms X doped single layer PbI2 are stable at room temperature, although substitutional atom X and I vacancy lead to the local structure deformation. Moreover, substitutional F, Cl and Br dopants do not induce the magnetism in doped single layer PbI2 due to same number of valence electron of F, Cl, Br and I, while ground states of I vacancy, S, P and Si doped system are magnetic and the magnetic moments induced by one I vacancy, S, P and Si atom are 1.0, 1.0, 2.0 and 3.0 μB, respectively. It is found that the distribution of the magnetic moment induced by I vacancy and doping atom relate to the hybridization between doping atom and its neighboring Pb and I atoms or the hybridization between Pb and I atoms around vacancy. Remarkably, although the spin–orbit coupling (SOC) induce spin splitting of the electronic bands due to the absence of inversion symmetry in I vacancy and nonmetallic atoms X doped single layer PbI2, the SOC does not alter the electron occupation of the bands near the Fermi level. As a result, the magnetic moment induced by I vacancy, S, P and Si atoms are not changed and the magnetic moment of F, Cl and Br doped single layer PbI2 are still zero after the inclusion of SOC.