High-Temperature Charge-Stripe Correlations in La1.675Eu0.2Sr0.125

Abstract

We use resonant inelastic x-ray scattering to investigate charge-stripe correlations in La 1.675 Eu 0.2 Sr 0.125 CuO 4 . By differentiating elastic from inelastic scattering, it is demonstrated that charge-stripe correlations precede both the structural low-temperature tetragonal phase and the transportdefined pseudogap onset. The scattering peak amplitude from charge stripes decays approximately as T −2 towards our detection limit. The in-plane integrated intensity, however, remains roughly temperature independent. Therefore, although the incommensurability shows a remarkably large increase at high temperature, our results are interpreted via a single scattering constituent. In fact, direct comparison to other stripe-ordered compounds (La 1.875 Ba 0.125 CuO 4 , La 1.475 Nd 0.4 Sr 0.125 CuO 4 , and La 1.875 Sr 0.125 CuO 4 ) suggests a roughly constant integrated scattering intensity across all these compounds. Our results therefore provide a unifying picture for the charge-stripe ordering in La-based cuprates. As charge correlations in La 1.675 Eu 0.2 Sr 0.125 CuO 4 extend beyond the low-temperature tetragonal and pseudogap phase, their emergence heralds a spontaneous symmetry breaking in this compound.

Generic character of charge and spin density waves in superconducting cuprates

“…Note that our data agree well with the high-resolution RIXS study of LESCO x = 0.125 reported in Ref. [19], in which the elastic scattering was measured directly (see SI Appendix VI), validating that the observations described above are not artifacts arising from, for example, the inelastic background subtraction method.…”

“…As previously demonstrated in Ref. [19] for x = 0.125, while the CDW peak intensity decreases with temperature, its integrated intensity is constant over the entire temperature range measured. We find that this behavior persists for all dopings, implying that the CDW amplitude is approximately temperatureindependent everywhere in the phase diagram where the CDW is present.…”

Charge order lock-in by electron-phonon coupling in La 1.675 Eu 0.2 Sr 0.125 CuO 4

“…Stripe order, revealed by the reflection at Q CDW = (δ, 0) with δ ≈ 0.24, weakens by about two orders of magnitude across this temperature range [see Fig. 3F and ( 30 )].…”

“…The inset displays the charge order correlation length ξ versus temperature. Open squares denote data from ( 30 ). Gray dashed lines in (A) and (C) and in (B) and (D) are respectively the DFT bare bond-stretching phonon dispersion (normalized to match our data) and the phonon spectral weight above T LTT fitted to a sin 2 (π h ) function.…”

Revival of Charge Density Waves and Charge Density Fluctuations in Cuprate High-Temperature Superconductors

“…The new feature of the experiments is the very broad BP (FWHM~ξ −1~0 .16-0.18 r.l.u. ), by now observed in many other families [55][56][57][58][59][60]. It has many peculiar properties (Figure 11), as follows: (i) it is present up to the highest measured T well above T*(p); (ii) the width (FWHM) and the correlation length are almost constant in T; the corresponding charge fluctuations are then non-critical and do not show any tendency to become critical at any finite T; and (iii) the characteristic energy ω ch has been measured by fitting the dynamical high-resolution spectra on the OP90 (and UD60) samples at T = 90 K, 150 K, 250 K and q = q c .…”