• DOI:10.1038/s41467-021-23317-3
• Corpus ID: 221266215

Evolution of spin excitations from bulk to monolayer FeSe

@article{Pelliciari2021EvolutionOS,
  title={Evolution of spin excitations from bulk to monolayer FeSe},
  author={J. Pelliciari and Şura Karakuzu and Qi Song and Riccardo Arpaia and Abhishek Nag and Matteo Rossi and J. Li and T Yu and X. Chen and Rui Peng and Mirian Garcia-Fernandez and Andrew C. Walters and Qisi Wang and J. F. Zhao and Giacomo Ghiringhelli and Donglai Feng and Thomas A. Maier and K. J. Zhou and Steven Johnston and Riccardo Comin},
  journal={Nature Communications},
  year={2021},
  volume={12}
}

• J. Pelliciari, Ş. Karakuzu, +17 authors R. Comin
• Published 21 August 2020
• Physics
• Nature Communications

In ultrathin films of FeSe grown on SrTiO3 (FeSe/STO), the superconducting transition temperature Tc is increased by almost an order of magnitude, raising questions on the pairing mechanism. As in other superconductors, antiferromagnetic spin fluctuations have been proposed to mediate SC making it essential to study the evolution of the spin dynamics of FeSe from the bulk to the ultrathin limit. Here, we investigate the spin excitations in bulk and monolayer FeSe/STO using resonant inelastic x-ray scattering (RIXS) and quantum Monte Carlo (QMC) calculations. Despite the absence of long-range magnetic order, bulk FeSe displays dispersive magnetic excitations reminiscent of other Fe-pnictides. Conversely, the spin excitations in FeSe/STO are gapped, dispersionless, and significantly hardened relative to its bulk counterpart. By comparing our RIXS results with simulations of a bilayer Hubbard model, we connect the evolution of the spin excitations to the Fermiology of the two systems revealing a remarkable reconfiguration of spin excitations in FeSe/STO, essential to understand the role of spin fluctuations in the pairing mechanism.