Exciton Dynamics, Fano Quantum Interference and d–d Excitation in the Single Crystal of Two‐Dimensional Antiferromagnetic Fe ₂ P ₂ S ₆

Excitonic quasiparticles and their interactions with phonons, magnons, and charge carriers may play a pivotal role in governing the optical properties and their correlation with magnetic interactions in two‐dimensional (2D) magnetic semiconductors. Further, in transition‐metal compounds, d–d electronic transitions, arising from excitations between crystal‐field‐split d orbitals, significantly influence the optical and magnetic properties, particularly in strongly correlated and low‐dimensional systems. Fe 2 P 2 S6, a layered antiferromagnetic semiconductor, offers a rich platform for studying the interplay between spin, charge, and lattice degrees of freedom in these 2D systems. In this work, we investigate the photoluminescence (PL) properties of Fe 2 P 2 S 6 to probe exciton dynamics, intra‐atomic transitions, and their temperature evolution. Two prominent d–d emission peaks are observed at ∼1.63 eV (D1) and ∼1.80 eV (D2), attributed to the crystal‐field‐split Fe 2+ states. An excitonic emission near the band edge is also identified, which exhibits a characteristic Fano asymmetric line shape. This asymmetry is attributed to the quantum interference between the discrete excitonic state and the d–d transition induced continuum (D2), revealing a Fano resonance behaviour. This exciton peak disappears well before the Néel temperature, indicating its faster destabilisation than magnetic ordering. Temperature‐dependent PL measurements show a quenching of the excitonic peak with increasing temperature. Our findings provide detailed insight into the optical excitation pathways in Fe 2 P 2 S 6 .