Short-ranged charge modulations in cuprates: r-space or k-space?
Electronic spatial charge modulations (CM) have been recently established as integral to the phase diagram of high-transition-temperature (high-Tc) cuprate superconductors. It is not yet understood if CM are involved in establishing high-Tc superconductivity, or are detrimental to it. The answer hinges on determining, in face of disorder, the relationship between periodicities of electronic CM and underlying lattice. Here we determine that CM are commensurate in the entire pseudogap region of Bi2Sr2CaCu2O8 phase diagram. The found commensurability points towards a strong coupling perspective on electrons, likely implying cooperation with superconductivity. We introduce a general analysis that exploits phase-sensitive measurements to find the periodicity of inhomogeneous modulations, and apply it to scanning tunneling microscopy images.
jeudi 12 novembre 2015