2026/03/31 by Qiang Luo, Shuhang Yang, Xiaoying Wang +4
Physics and Astronomy · #cond-mat.str-el
paper · pdf · doi:10.1103/l2t3-m78p
published as Phys. Rev. B 114, 034426 (2026) · 11+11 pages, 8+2 figures
arxiv created 2026/08/01 · arxiv updated 2026/08/04
Despite extensive research, the precise spin Hamiltonian of the van der Waals antiferromagnet NiPS3 -- which hosts a zigzag-ordered ground state -- remains debated. While consensus has emerged on ferromagnetic nearest-neighbor (J1) and antiferromagnetic third-nearest-neighbor (J3) Heisenberg interactions, recent studies suggest a biquadratic (B) exchange term may also play a role, though its estimated magnitude varies widely. To address this controversy, we perform density functional theory calculations and extract a positive biquadratic interaction with B/J3 ≈ 0.44. Within the minimal J1-J3-B model, we show that these parameters naturally stabilize zigzag ordering using minimally augmented spin-wave theory. Density-matrix renormalization group calculations further validate our extracted parameters as a reasonable description of the ground state. Although fully resolving the spin Hamiltonian of NiPS3 requires further investigation, our findings provide new insights into its biquadratic interaction.