Electron orbital mapping of SrTiO3 using electron energy-loss spectroscopy

The visualization of electron orbitals in real space is expected as a next-generation technique that has been evolved from high spatial resolution electron microscopy. Core excitation electron energy-loss spectra with a high signal-to-noise ratio were recorded in a scanning transmission electron microscope with high spatial resolution to directly observe the electron orbitals in real space. We experimentally demonstrate that anisotropic distributions of oxygen 2p orbitals in SrTiO3 were observed in real space and were dependent on the difference in the chemical bonds between Ti and O atoms. The results open the door to the visualization of electronic orbitals with electron microscopes.