We investigate whether the spin or charge degrees of freedom are responsible for the nodal gap in underdoped cuprates by performing inelastic neutron scattering and x-ray diffraction measurements on La2−xSrxCuO4, which is on the edge of the antiferromagnetic phase. We found that fluctuating incommensurate spin-density-wave (SDW) with a the bottom part of an hourglass dispersion exists even in this magnetic sample. The strongest component of these fluctuations diminishes at the same temperature where the nodal gap opens. X-ray scattering measurements on the same crystal show no signature of charge-density-wave (CDW). Therefore, we suggest that the nodal gap in the electronic band of this cuprate opens due to fluctuating SDW with no contribution from CDW.
@article{arxiv.1612.06864,
title = {Opening a nodal gap by fluctuating spin-density-wave in lightly doped La$_{2-x}$Sr$_x$CuO$_4$},
author = {Itzik Kapon and David S. Ellis and Gil Drachuck and Galina Bazalitski and Eugen Weschke and Enrico Schierle and Jörg Strempfer and Christof Niedermayer and Amit Keren},
journal= {arXiv preprint arXiv:1612.06864},
year = {2017}
}