Exciton Dynamics, Fano Quantum Interference and d–d Excitation in the Single Crystal of Two-Dimensional Antiferromagnetic Fe2P2S6

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Contributors

Abstract

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. Fe2P2S6, 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 Fe2P2S6 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 Fe2+ 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 Fe2P2S6.

Details

Original languageEnglish
JournalPhysica Status Solidi - Rapid Research Letters
Publication statusAccepted/In press - 2025
Peer-reviewedYes

Keywords

Keywords

  • crystal field, d–d transition, exciton, Fano, photoluminescence