Direct imaging of orbitals in quantum materials

The electronic states of quantum materials based on transition metal, rare earth and actinide elements are dominated by elec trons in the d and f orbitals intertwined with the strong band formation of the solid. Until now, to estimate which specific orbitals contribute to the ground state and thereby determine their physical properties we have had to rely on theoretical calcu lations combined with spectroscopy. Here, we show that s core level non resonant inelastic X ray scattering can directly image the active orbital in real space, without the necessity for any modelling. The power and accuracy of this new technique is shown using the textbook example, x2 amp; 8722;y2 3z2 amp; 8722;r2 orbital of the Ni2 ion in NiO single cryst