Spin-crossover induced ferromagnetism and layer stacking-order change in pressurized 2D antiferromagnet MnPS3

• Published in: Physical chemistry chemical physics : PCCP 2021-04, Vol.23 (16), p.9679-9685
• Main Authors: Zhang, Hanxing, Niu, Caoping, Zhang, Jie, Zou, Liangjian, Zeng, Zhi, Wang, Xianlong
• Format: Article
• Language: English
• Subjects: Antiferromagnetism; Crossovers; Ferromagnetism; Metal compounds; Metal-insulator transition; Stacking; Superconductivity; Transition metal compounds
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/d0cp04917d

Spin-crossover combined with metal–insulator transition and superconductivity has been found in 2D transition-metal phosphorous trichalcogenides when tuning them by high pressure. Simulation of such intriguing spin-crossover behaviors is crucial to understanding the mechanism. The Hubbard U correction is widely used to describe the strong on-site Coulomb interaction in the d electrons of transition-metal compounds, while the U values are sensitive to the crystal field and spin state varying greatly with pressure. In this work, we show that taking MnPS3 as an example and based on a uniform parameter set, the hybrid functional calculations give a spin-crossover pressure of 35 GPa consistent with experimental observation (30 GPa), which is less than half of the existing reported value (63 GPa) using the Hubbard U correction. Notably, we find a spin-crossover induced transition from an antiferromagnetic semiconductor with monoclinic stacking-order to a ferromagnetic semiconductor with rhombohedral stacking-order, and the ferromagnetism originates from the partially occupied t2g orbitals. Different from previous understanding, the Mott metal–insulator transition of MnPS3 does not occur simultaneously with the spin-crossover but in a pressurized low-spin phase.