Revisiting Cu63 NMR evidence for charge order in superconducting La1.885Sr0.115

Abstract

The presence of charge and spin stripe order in the La2CuO4-based family of superconductors continues to lead to new insight on the unusual ground state properties of high Tc cuprates. Soon after the discovery of charge stripe order at T charge 65 K in Nd 3+ co-doped La1.48Nd0.4Sr0.12CuO4 (Tc 6 K) [Tranquada et al., Nature 375 (1995) 561], Hunt, Singer et al. demonstrated that La1.48Nd0.4Sr0.12CuO4 and superconducting La2−xSrxCuO4 with x ∼ 1/8 (Tc 30 K) share nearly identical NMR anomalies near T charge of the former [Phys. Rev. Lett. 82 (1999) 4300]. Their inevitable conclusion that La1.885Sr0.115CuO4 also undergoes charge order at a comparable temperature became controversial, because diffraction measurements at the time were unable to detect Bragg peaks associated with charge order. Recent advances in x-ray diffraction techniques finally led to definitive confirmations of the charge order Bragg peaks in La1.885Sr0.115CuO4 with an onset at as high as T charge 80 K. Meanwhile, improved instrumental technology has enabled routine NMR measurements that were not feasible two decades ago. Motivated by these new developments, we revisit the charge order transition of a La1.885Sr0.115CuO4 single crystal based on 63 Cu NMR techniques. We demonstrate that 63 Cu NMR properties of the nuclear spin Iz = − 1 2 to + 1 2 central transition below T charge exhibit unprecedentedly strong dependence on the measurement time scale set by the separation time τ between the 90 • and 180 • radio frequency pulses; a new kind of anomalous, very broad wing-like 63 Cu NMR signals gradually emerge below T charge only for extremely short τ 4 µs, while the spectral weight I N ormal of the normal NMR signals is progressively wiped out. The NMR linewidth and relaxation rates depend strongly on τ below T charge , and their enhancement in the charge ordered state indicates that charge order turns on strong but inhomogeneous growth of Cu spin-spin correlations. I.arXiv:1712.07777v1 [cond-mat.supr-con]

Anomalies in the pseudogap phase of the cuprates: competing ground states and the role of umklapp scattering

“…The first value should now be familiar to the reader, coinciding with features in both the c-axis optical conductivity and giant phonon anomaly measurements on type B cuprates. Could this constitute an example where at high temperatures one probes properties of a close-in-energy type B ground state, while at low-temperatures that system (Tranquada et al 1995) c-axis transport (Li et al 2007) Inelastic X-ray scattering (Miao et al 2017 La 2−x Sr x CuO 4 × Nuclear magnetic resonance (Imai et al 2017) X-ray diffraction (Thampy et al 2014, Croft et al 2014 Non-linear optical response (Rajasekaran et al 2018) Hourglass magnon spectrum (Chan et al 2016)…”

“…Only in the last few years, with advances in X-ray scattering techniques, has the presence of charge ordering been revealed (Thampy et al 2014, Croft et al 2014. Recent work by Imai and coworkers (Imai et al 2017) undertook a careful and detailed NMR study of LSCO, finding a similar interplay between CDW and SDW order as in LBCO, but with detailed patterns that are strongly modified by disorder. They also show that the amplitude of the CDW is very small, explaining why initial x-ray scattering experiments could not observe the associated Bragg peaks.…”

Period 4 stripe in the extended two-dimensional Hubbard model

“…While enormous experimental and theoretical effort has been invested to understand the physics of high-T c superconductivity in copper-oxide materials (or cuprates) [1], a full understanding of their phase diagram is still lacking [2][3][4]. In the underdoped region of various cuprate materials, signatures of multiple broken symmetries have been inferred from experiments -from neutron scattering [5][6][7][8][9], x-ray resonant scattering [10][11][12], nuclear magnetic resonant microscopy [13,14] to scanning tunneling microscopy [15][16][17][18][19] -collectively providing evidence for simultaneous charge and spin modulated states, coexisting or competing with superconductivity, called stripes [20][21][22][23][24][25][26][27][28][29][30][31][32].…”

La139 NMR investigation of the charge and spin order in a La1.885Sr0.115CuOArsenault1, Takahashi2, Imai3 et al. 2018Phys. Rev. BSelf Cite125120View full textAdd to dashboardCite

“…For example, 63 Cu NMR and NQR (Nuclear Quadrupole Resonance) linewidth and relaxation rates grow exponentially in the paramagnetic state of undoped La 2 CuO 4 due to the exponential growth of the spin-spin correlation length ξ [3,4]. Accordingly, detection of the paramagnetic 63 Cu NMR and NQR signals becomes difficult below ∼ 400 K, nearly 100 K above the three-dimensional Néel transition at T N 325 K. This is also the fundamental reason behind the gradual disappearance of 63 Cu NMR signals in the charge ordered state of La 2 CuO 4 -based cuprates near the doping concentration around x ∼ 1/8, because a growing volume fraction of CuO 2 planes have divergently strong spin correlations [5][6][7].…”