Variation between Antiferromagnetism and Ferrimagnetism in NiPS₃ by Electron Doping

Abstract

To electrically control magnetic properties of material is promising toward spintronic applications, where the investigation of carrier doping effects on antiferromagnetic (AFM) materials remains challenging due to their zero net magnetization. In this work, the authors find electron doping dependent variation of magnetic orders of a 2D AFM insulator NiPS 3 , where doping concentration is tuned by intercalating various organic cations into the van der Waals gaps of NiPS 3 without introduction of defects and impurity phases. The doped NiPS 3 shows an AFM-ferrimagnetic (FIM) transition at a doping level of 0.2-0.5 electrons/cell and a FIM-AFM transition at a doping level of ≥0.6 electrons/cell. The authors propose that the found phenomenon is due to competition between Stoner exchange dominated inter-chain ferromagnetic order and super-exchange dominated AFM order at different doping level. The studies provide a viable way to exploit correlation between electronic structures and magnetic properties of 2D magnetic materials for realization of magnetoelectric effect.

Spin wave Hamiltonian and anomalous scattering in NiPS$_3$

“…Our perturbation theory results are also in close agreement with the results in Ref. [12] obtained from fitting total energies of magnetic configurations simulated with DFT+U.…”

“…NiPS 3 has very strong spin-charge coupling [5,6], and because of this is already being made into workable devices [7,8]. Its magnetic excitations have been measured with powder and single-crystal neutron scattering [9,10] and density functional theory shows dominant J 3 exchange interaction [11,12], but certain features in its magnetic Hamiltonian (namely the low energy modes) remain imperfectly understood. Perhaps most intriguingly, X-ray, photoluminescence, and optical absorption spectroscopies show a bound exciton state consistent with Zhang-Rice triplet formation between Ni and surrounding S ligands [13], which suggests the magnetism is far from conventional.…”

Dual Character of the Insulating State in the van der Waals Fe1–xNixPS3 Alloyed Compounds

“…The properties of MPX 3 materials can be tuned in different ways using intercalation between layers or adsorption of different species on top. ,− Here, MPX 3 , for example, can be converted from the antiferromagnetic into ferromagnetic state, and such systems might find broad applications in different areas. Also the mutual substitution of S and Se allows making a fine-tuning of the band gap in the MPX 3 materials; however, the attempts to prepare the ordered Janus compounds failed due to the large dipole moment appearing in the single MPX 3 layers as a result of the imbalance of charge distribution between S and Se …”

Engineering Magnetism and Superconductivity in van der Waals Materials via Organic‐Ion Intercalation

“…Simultaneously, Mi et al performed a similar study on the evolution of the magnetism of NiPS 3 upon electrochemical intercalation of different alkylammonium cations. [83] Guest species exhibiting different sizes were employed for establishing a connection between the magnetism and the molecular size. They discovered that the doping level, controlled mainly by the steric hindrance of the guest molecule, is one of the key points to modulate the magnetic ordering between Ni ions.…”