"Direct observation of bulk charge modulations in optimally doped Bi1.5Pb0.6Sr1.54CaCu2O8+δ"

M. Hashimoto: G. Ghiringhelli, W.-S. Lee, G. Dellea, A. Amorese, C. Mazzoli, K. Kummer, N. B. Brookes, B. Moritz, Y. Yoshida, H. Eisaki, Z. Hussain, T. P. Devereaux, Z.-X. Shen, and L. Braicovich ; Physical Review B, 06/30/14.

Additional Authors: G. Ghiringhelli, W.-S. Lee, G. Dellea, A. Amorese, C. Mazzoli, K. Kummer, N. B. Brookes, B. Moritz, Y. Yoshida, H. Eisaki, Z. Hussain, T. P. Devereaux, Z.-X. Shen, and L. Braicovich

Abstract:

Abstract

Bulk charge density modulations, recently observed in high critical-temperature (Tc) cuprate superconductors, coexist with the so-called pseudogap and compete with superconductivity. However, its direct observation has been limited to a narrow doping region in the underdoped regime. Using energy-resolved resonant x-ray scattering we have found evidence for such bulk charge modulations, or soft collective charge modes (soft CCMs), in optimally doped Bi1.5Pb0.6Sr1.54CaCu2O8+δ (Pb-Bi2212) around the summit of the superconducting dome with momentum transfer q∥∼0.28 reciprocal lattice units (r.l.u.) along the Cu-O bond direction. The signal is stronger at TTc than at lower temperatures, thereby confirming a competition between soft CCMs and superconductivity. These results demonstrate that soft CCMs are not constrained to the underdoped regime, suggesting that soft CCMs appear across a large part of the phase diagram of cuprates and are intimately entangled with high-Tc superconductivity.

DOI: http://dx.doi.org/10.1103/PhysRevB.89.220511