Edwards-Anderson parameter and local Ising nematicity in FeSe revealed via NMR spectral broadening

The NMR spectrum of FeSe shows a dramatic broadening on cooling towards the bulk nematic phase at T-s = 90 K, due to the formation of a quasistatic, short-range-ordered nematic domain structure. However, a quantitative understanding of the NMR broadening and its relationship to the nematic susceptibility is still lacking. Here, we show that the temperature and pressure dependence of the broadening is in quantitative agreement with the mean-field Edwards-Anderson parameter of an Ising-nematic model in the presence of random-field disorder introduced by nonmagnetic impurities. Furthermore, these results reconcile the interpretation of NMR and Raman spectroscopy data in FeSe under pressure.

Automated summary

The study provides a quantitative explanation for the temperature and pressure dependence of the NMR broadening in FeSe using an Ising-nematic model, showing the relationship between this phenomenon and nematic susceptibility. These results help reconcile the interpretation of NMR and Raman spectroscopy data in FeSe under pressure.