Observation of Electronic Inhomogeneity and Charge Density Waves in a Bilayer La2-2xSr1+2xMn2O7 Single Crystal

We employed a scanning tunneling microscope to image the (001) surface topography and local density of states (LDOS) in La2-2xSr1+2xMn2O7 (x = 0.32, LSMO) single crystals below the Curie temperature (T-C approximate to 120 K). The LDOS maps revealed a stripelike modulation propagating along the tetragonal a axis with a wavelength of about 16 angstrom, which is indicative of a charge density wave (CDW). The observed CDW in the x = 0.32 sample is far from the Fermi surface nesting instability as compared with the data of angle resolved photoemission spectroscopy in an x = 0.40 sample. The stripe model developed previously for cuprates can explain the observed CDW in our LSMO sample, indicating that competing interactions between localized and itinerant phases are the origin of the spatial modulations present intrinsically in cuprates and manganites.