# Direct imaging of orbitals in quantum materials

## TL;DR

This paper introduces a novel x-ray scattering technique that directly images active orbitals in quantum materials, bypassing the need for theoretical modeling, demonstrated on NiO's nickel ion orbital.

## Contribution

The paper presents a new experimental method, s-NIXS, capable of directly visualizing orbitals in real space without relying on theoretical calculations.

## Key findings

- s-NIXS accurately images orbitals in quantum materials.
- The technique is demonstrated on NiO's Ni$^{2+}$ orbital.
- It provides a model-free approach to orbital characterization.

## Abstract

The spectacular physical properties of quantum materials based on transition metal, rare earth, and actinide elements continue to challenge our comprehension of solid state physics and chemistry. The electronic states of these materials are dominated by the $d$ and $f$ wave functions intertwined with the strong band formation of the solid. In order to estimate which wave functions contribute to the ground state formation, we have had to rely, until now, on theoretical calculations combined with spectroscopy. Here we show that $s$-core-level non-resonant inelastic x-ray scattering ($s$-NIXS) can directly image the active orbital in real space, without the necessity of any modeling. The power and accuracy of this new technique is shown using the text-book example, x$^2$-y$^2$/3$z^2$-r$^2$ orbital of the Ni$^{2+}$ ion in NiO single crystal.