Spin-polarized ground states and defect-induced intrinsic magnetism in fully hydrogenated rectangular phosphorene quantum dot

Abstract

Defect-induced magnetism in fully hydrogenated rectangular phosphorene quantum dots is investigated in this study using spin-polarized density functional theory (DFT) computations. The main goal is to examine the correlation between electronic states and intrinsic magnetic properties. Results demonstrate that introducing a vacancy at the quantum dot’s center and substituting a Si atom for the middle P atom result in a doublet state with a total magnetic moment of 1 µB. Spin density in these magnetic systems concentrates around the middle site and diminishes towards the cluster edges. Conversely, substituting the N atom for the intermediate P atom yields a non-magnetic system, consistent with electron occupation theory. In contrast to graphene, our investigation of the magnetic quantum dots’ spectrum shows the existence of vacant mid-gap states, suggesting that the magnetism is linked to electrical states with half-filled orbitals close to the highest occupied molecular orbital (HOMO). Furthermore, our findings indicate that energy gaps and zero energy states are responsive to changes in parallel electric fields, affecting the local spin density of magnetic atoms. This suggests potential applications in qubit implementation.

Graphical abstract