The magnetic ground-state configuration of iron selenide (FeSe) has been a topic of debate, with experimental evidence suggesting the stripe spin fluctuations as predominant at low temperatures, while density functional theory calculations using the exchange-correlation (XC) functional of the generalized gradient approximation (GGA) have historically predicted the antiferromagnetic (AFM) dimer configuration. In this study, we utilize the restored-regularized SCAN $\left({\mathrm{r}}^2\mathrm{SCAN}\right)$ functional, a variant of the strongly constrained and appropriately normed (SCAN) meta-GGA, to investigate the magnetic configurations of FeSe. It is found that ${\mathrm{r}}^2\mathrm{SCAN}$ predicts a stripe-AFM ground-state configuration with an antiparallel spin alignment between layers. The energy difference between the parallel and antiparallel interplanar spin alignments is approximately 1.7 meV/atom, predicting a significant but previously unreported interlayer spin coupling not yet observed by experiments. The present study underscores the importance of accurate XC functionals, such as ${\mathrm{r}}^2\mathrm{SCAN}$, in predicting the magnetic ground-state configuration of complex materials like FeSe, highlighting its potential to predict magnetic interactions more reliably than traditional GGA functionals by adhering to exact constraints.

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• Antiferromagnetism
• Magnetic order
• Microstructure
• Paramagnetism
• Paramagnets
• Strongly correlated systems
• Superconductors
• Density functional theory
• First-principles calculations
• Meta-GGA