Heat transport ofLa2−yEuyCuO

Abstract

To study the rare-earth doping effect on the phonon heat transport of La-based cuprates and shed light on the mechanism of phonon scattering, both ab-plane and c-axis thermal conductivities (κ ab and κc) are measured for La2−yEuyCuO4 (y = 0, 0.02 and 0.2) and La1.88−yEuySr0.12CuO4 (y = 0 and 0.2) single crystals. It is found that the phonon peak (at 20 -25 K) in κ ab (T ) of La2−yEuyCuO4 shows an anomalous Eu-doping dependence: it completely disappears for y = 0.02, which is discussed to be due to the local lattice distortions around Eu dopants, and reappears for y = 0.2 with much smaller peak magnitude compared to y = 0 sample. In contrast to the strong suppression of the phonon peak in Eu-doped La2CuO4, Eu-doping to La1.88Sr0.12CuO4 enhances the low-T phonon heat transport that results in the reappearance of the phonon peak in this chargecarrier-doped system. The data clearly show that the establishment of static stripe phase rather than the structural change is responsible for the reappearance of phonon peak.

Neutron scattering study of spin ordering and stripe pinning in superconductingLa1.93Sr0.07CuO4

“…In the case of LBCO, complete or nearly complete ordering of the tilts results in a substantial increase in the thermal conductivity below the transition temperature [31]. In contrast, thermal conductivity measurements on LSCO with x ≥ 0.1 show no significant recovery at low temperature [85,86], consistent with the continued presence of dissipative fluctuations.…”

Effect of stripe ordering on the anisotropic superconductivity in La1.6−xNd0.4SrxCuO4 single crystals

“…The difference between the c-axis and ab-plane superconductivities seems to be related to the evolution of the anisotropy with the enhancement of the stripe order. The anisotropic behavior raised by static stripe phase was also reported by measuring thermal conductivity of La 1.88Ày Eu y Sr 0.12 CuO 4 , in which the stripe order obviously suppress the ab-plane phonon scattering but has few effect on the caxis one [8]. To convince the stripe order induced anisotropy, it is necessary to systematically investigate the evolution of the anisotropic resistivity in a static stripe system.…”

Probing the connections between superconductivity, stripe order, and structure in La1.905Ba0.095CuWen1, Xu2, Xu3 et al. 2012Phys. Rev. B256380View full textAdd to dashboardCite

“…Together with the absence of any significant change with H ⊥ , κ ab appears to be dominated by phonons. In studies of related materials, 82,83 it has been proposed that ordering of charge stripes could decrease the scattering rate of phonons, thus increasing the thermal conductivity. In the present case, such an explanation seems unlikely as the stripe ordering is weak, while the change in κ ab is substantial, especially in comparison with comparably doped La 2−x Sr x CuO 4 .…”