${}^{139}$La and ${}^{63}$Cu NMR investigation of charge order in La${}_2$CuO${}_{4+y}$ ($T_c=42$K)

Abstract

We report ${}^{139}$La and ${}^{63}$Cu NMR investigation of the successive charge order, spin order, and superconducting transitions in super-oxygenated La${}_2$CuO${}_{4+y}$ single crystal with stage-4 excess oxygen order at $T_{stage}\simeq 290$ K. We show that the stage-4 order induces tilting of CuO${}_6$ octahedra below $T_{stage}$, which in turn causes ${}^{139}$La NMR line broadening. The structural distortion continues to develop far below $T_{stage}$, and completes at $T_{charge}\simeq 60$ K, where charge order sets in. This sequence is reminiscent of the the charge order transition in Nd co-doped La${}_{1.88}$Sr${}_{0.12}$CuO${}_4$ that sets in once the low temperature tetragonal (LTT) phase is established. We also show that the paramagnetic ${}^{63}$Cu NMR signals are progressively wiped out below $T_{charge}$ due to enhanced low frequency spin fluctuations, but the residual ${}^{63}$Cu NMR signals continue to exhibit the characteristics expected for optimally doped superconducting CuO${}_2$ planes. This indicates that charge order in La${}_2$CuO${}_{4+y}$ does not take place uniformly in space. Low frequency Cu spin fluctuations as probed by ${}^{139}$La nuclear spin-lattice relaxation rate are mildly glassy, and do not exhibit critical divergence at $T_{spin}$($\simeq T_c$)=42 K. These findings, including the spatially inhomogeneous nature of the charge ordered state, are qualitatively similar to the case of La${}_{1.885}$Sr${}_{0.115}$CuO${}_4$ [T. Imai et al., Phys. Rev. B 96 (2017) 224508, and A. Arsenault et al., Phys. Rev. B 97 (2018) 064511], but both charge and spin order take place more sharply in the present case.

Final version accepted for publication in PRB

References in corpus (7)

• Resonant x-ray scattering studies of charge order in cuprates
• Charge density wave fluctuations in La2-xSrxCuO4 and their competition with superconductivity
• Rotated stripe order and its competition with superconductivity in La${}_{1.88}$Sr${}_{0.12}$CuO${}_4$
• Similar glassy features in the NMR response of pure and disordered La1.88Sr0.12CuO4
• Melting of the Na layers in solid Na0.8CoO2
• Revisiting ${}^{63}$Cu NMR evidence for charge order in superconducting La${}_{1.885}$Sr${}_{0.115}$CuO${}_4$
• Magnetic field induced anisotropy of ${}^{139}\mathrm{La}$ spin-lattice relaxation rates in stripe ordered ${\mathrm{La}}_{1.875}{\mathrm{Ba}}_{0.125}{\mathrm{CuO}}_4$

Cited by in corpus (4)

• Charge-stripe order, antiferromagnetism, and spin dynamics in the cuprate-analog nickelate La${}_4$Ni${}_3$O${}_8$
• Tuning the interplay between nematicity and spin fluctuations in Na${}_{1-x}$Li${}_x$FeAs superconductors
• Nature of the magnetic stripes in fully oxygenated La${}_2$CuO${}_{4+y}$
• Revisiting the ${}^{63}$Cu NMR signature of charge order in La${}_{1.875}$Ba${}_{0.125}$CuO${}_4$