Two- and three-dimensional incommensurate modulation in optimally-doped Bi2Sr2CaCu2O8+δ

X-ray scattering measurements on optimally doped single crystal samples of the high-temperature superconductor Bi2Sr2CaCu2O8+δ reveal the presence of three distinct incommensurate charge modulations, each involving a roughly fivefold increase in the unit cell dimension along the b direction. The strongest scattering comes from the well known (H,K±0.21,L) modulation and its harmonics. However, we also observe broad diffraction which peak up at …