Evolution of spin excitations from bulk to monolayer FeSe
Journal article, 2021
In ultrathin films of FeSe grown on SrTiO (FeSe/STO), the superconducting transition temperature T 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.
Author
Jonathan Pelliciari
Brookhaven National Laboratory
Massachusetts Institute of Technology (MIT)
Seher Karakuzu
Oak Ridge National Laboratory
Qi Song
Fudan University
Riccardo Arpaia
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics
Polytechnic University of Milan
Abhishek Nag
Diamond Light Source
Matteo Rossi
Polytechnic University of Milan
Jiemin Li
Diamond Light Source
Tianlun Yu
Fudan University
Xiaoyang Chen
Fudan University
Rui Peng
Fudan University
M. Garcia-Fernandez
Diamond Light Source
Andrew C. Walters
Diamond Light Source
Q. Wang
Fudan University
Jun Zhao
Fudan University
Giacomo Ghiringhelli
Polytechnic University of Milan
Donglai Feng
Fudan University
Thomas A. Maier
Oak Ridge National Laboratory
Ke Jin Zhou
Diamond Light Source
Steven Johnston
University of Tennessee
Riccardo Comin
Massachusetts Institute of Technology (MIT)
Nature Communications
2041-1723 (ISSN) 20411723 (eISSN)
Vol. 12 1 3122Evolution of nanoscale charge order in superconducting YBCO nanostructures
Swedish Research Council (VR) (2017-00382), 2017-07-01 -- 2020-06-30.
Subject Categories
Other Physics Topics
Theoretical Chemistry
Condensed Matter Physics
DOI
10.1038/s41467-021-23317-3
PubMed
34035254