We report a persistent low-energy phonon broadening around qB ∼ 0.28 r.l.u. along the Cu-O bond direction in the high-Tc cuprate Bi2Sr2CaCu2O 8+δ (Bi-2212). We show that such broadening exists both inside and outside the conventional charge density wave (CDW) phase, via temperature dependent measurements in both underdoped and heavily overdoped samples. Combining inelastic hard x-ray scattering, diffuse scattering, angle-resolved photoemission spectroscopy, and resonant soft x-ray scattering at the Cu L3-edge, we exclude the presence of a CDW in the heavily overdoped Bi-2212 similar to that observed in the underdoped systems. Finally, we discuss the origin of such anisotropic low-energy phonon broadening, and its potential precursory role to the CDW phase in the underdoped region. arXiv:1804.09286v1 [cond-mat.str-el]

Anomalous electric response of La2-x Sr x CuO4 thin film at Sr doping levels of x≈1/4 and 1/16 is observed when charge moves along the c axis. The capacitance C t of the Pd/La2-x Sr x CuO4/SrTiO3/Pd structure increases sharply, exceeding the capacitance C STO of the Pd/SrTiO3/Pd structure. Oscillatory negative voltage is observed in 4-terminal resistivity measurements of La2-x Sr x CuO4 thin film using Pd electrodes at small current. These phenomena are explained by a model of the spatial ordered state in which CuO2 layers of La2-x Sr x CuO4 is replete with O hole pairs.

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