Large-Tiny Spin-Stripe SDW Order in La3Ni2O7 via 139La-NQR Spectroscopy: Reconsideration Based on the Am2m Structure
Abstract
The lower-symmetry Am2m structure was recently proposed as the intrinsic ambient-pressure phase of La3Ni2O7 based on synchrotron x-ray diffraction, whereas earlier studies investigated its properties assuming the commonly accepted Amam structure. Here, we reexamine the crystal structure in La3Ni2O7 and the spin configuration of spin-density-wave (SDW) state via 139La nuclear quadrupole resonance (NQR). The observation of two distinct La(2) sites in the NQR spectra is naturally accounted for by the Am2m structure without any special assumptions, whereas it cannot be reconciled within the Amam framework. Within the Am2m framework, we reanalyze the spin configuration of the SDW phase and identify it as a large-tiny spin-stripe structure, arising naturally from two inequivalent Ni sites with large and tiny magnetic moments. These results establish the itinerant nature of the SDW order at ambient pressure in La3Ni2O7, providing a basis for understanding its relationship to the emergence of high-Tc superconductivity under high pressure.
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BibTeX
@misc{yashima2026largetiny,
title = {{Large-Tiny Spin-Stripe SDW Order in La$_3$Ni$_2$O$_7$ via $^139$La-NQR Spectroscopy: Reconsideration Based on the $Am2m$ Structure}},
author = {Mitsuharu Yashima and Hongnam Lee and Takumi Ino and Nina Seto and Masataka Kakoi and Hiroya Sakurai and Yoshihiko Takano and Hidekazu Mukuda},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.20446},
eprint = {2610.20446},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.20446},
}
RIS
TY - UNPB
TI - Large-Tiny Spin-Stripe SDW Order in La_3Ni_2O_7 via ^139La-NQR Spectroscopy: Reconsideration Based on the Am2m Structure
AU - Mitsuharu Yashima
AU - Hongnam Lee
AU - Takumi Ino
AU - Nina Seto
AU - Masataka Kakoi
AU - Hiroya Sakurai
AU - Yoshihiko Takano
AU - Hidekazu Mukuda
PY - 2026
DA - 2026/10/14
PB - arXiv
DO - 10.48550/arxiv.2610.20446
UR - https://arxiv.org/abs/2610.20446
AB - The lower-symmetry Am2m structure was recently proposed as the intrinsic ambient-pressure phase of La_3Ni_2O_7 based on synchrotron x-ray diffraction, whereas earlier studies investigated its properties assuming the commonly accepted Amam structure. Here, we reexamine the crystal structure in La_3Ni_2O_7 and the spin configuration of spin-density-wave (SDW) state via ^139La nuclear quadrupole resonance (NQR). The observation of two distinct La(2) sites in the NQR spectra is naturally accounted for by the Am2m structure without any special assumptions, whereas it cannot be reconciled within the Amam framework. Within the Am2m framework, we reanalyze the spin configuration of the SDW phase and identify it as a large-tiny spin-stripe structure, arising naturally from two inequivalent Ni sites with large and tiny magnetic moments. These results establish the itinerant nature of the SDW order at ambient pressure in La_3Ni_2O_7, providing a basis for understanding its relationship to the emergence of high-T_c superconductivity under high pressure.
ER -