Dynamical Properties of Charged Stripes inLa2−xSrxCuO4

Abstract

Inelastic light-scattering spectra of underdoped La2-xSrxCuO4 single crystals are presented which provide direct evidence of the formation of quasi-one-dimensional charged structures in the two-dimensional CuO2 planes. The stripes manifest themselves in a Drude-like peak at low energies and temperatures. The selection rules allow us to determine the orientation to be along the diagonals at x=0.02 and along the principal axes at x=0.10. The electron-lattice interaction determines the correlation length which turns out to be larger in compound classes with lower superconducting transition temperatures. Temperature is the only scale of the response at different doping levels demonstrating the importance of quantum critical behavior.

First-order-type effects inYBa2Cu3O6+xat the onset of superconductivity

“…This rotation was also seen in the low-energy electronic Raman spectra where the ordering-related response flips symmetry [8].…”

“…The purpose is to gain insight into the nature of the onset of superconductivity at p sc1 ≈ 0.06 and into possible discrimination criteria to the "low-T c " compound La 2−x Sr x CuO 4 (LSCO) studied earlier [7,8,17]. For 0 < p < p sc1 we find spectral features strikingly similar to those in LSCO and conclude that the diagonal stripe-like superstructure is universal.…”

“…Since the polarizations of the incident and the scattered photons can be adjusted independently, many of the excitations can be sorted out via the selection rules. For instance, the transport properties of conduction electrons can be measured independently in different regions of the Brillouin zone [15,16], and the orientation of (fluctuating) charged stripes can be determined [8]. A detailed model calculation [17] demonstrated that in addition to the symmetry selection rules the dependence on energy and temperature of the response related to stripes can be understood quantitatively (Fig.…”

“…In most of the cases fluctuating order prevails, and it is particularly hard to detect the charge part [5,13]. Raman spectroscopy was found to be a viable method [8].Inelastic (Raman) scattering of light is capable of probing most of the excitations in a solid including lattice vibrations, spins, and electrons, as well as their interactions [15]. Since the polarizations of the incident and the scattered photons can be adjusted independently, many of the excitations can be sorted out via the selection rules.…”

“…In most of the cases fluctuating order prevails, and it is particularly hard to detect the charge part [5,13]. Raman spectroscopy was found to be a viable method [8].…”