Institute for Quantum Materials and Technologies

Working Group Inelastic Photon Scattering

Head: Prof. Dr. Matthieu Le Tacon

We explore the dynamic of spin, charge, orbital and lattice degrees of freedoms in strongly correlated transition metal oxides using inelastic photon scattering techniques to gain insights about competing ordering tendencies in these materials. To this endeavor, we exploit photons from a large fraction of the electromagnetic spectrum to map out materials collective excitations in the energy-momentum space, akin to inelastic neutron scattering.

Inelastic scattering of visible photons (Raman scattering with typical photon energies of a few eV) is a highly versatile technique that allows us to probe the dynamics of solids at the center of the Brillouin zone (q = 0) with very high energy resolution and in a large variety of environments (low temperatures, high pressures, uniaxial or epitaxial strains). Those are complemented with resonant inelastic x-ray scattering (RIXS) in the soft (respectively hard) x-ray range for 3d (respectively 5d) transition metal oxides to study the dispersion of magnetic and/or orbital excitations, akin to inelastic neutron scattering, as well as with non-resonant inelastic hard x-ray scattering to study the dispersion of phonons. These x-ray based methods are carried out on various synchrotron sources all around the world.

Left: uniaxial pressure cell developed for transmission x-ray diffraction and inelastic scattering experiment.
Right: Elastic x-ray scattering intensity in high temperature superconducting YBCO along the reciprocal space direction (0, 0.315,L) with and without uniaxial stress. The broad peak centered at L ~ 6.0 in the absence of external stress corresponds to a quasi-2D, short-range charge-density-wave (CDW). Under stress, a long range 3D, characterized by the sharp peak around L=7.0 can be induced.
Inelastic x-ray scattering intensity as function of energy and momentum showing strong phonon softening next to CDW superstructure peak in underdoped YBCO.


Current research interests:


Members (in alphabetical order)
Name Tel
paolo battistoniGgn9∂kit edu
arun.jaiswalGgn9∂kit edu
tom lacmanGgn9∂kit edu
matthieu.taconGgn9∂kit edu
sofia.souliouGgn9∂kit edu
yi yaoGgn9∂kit edu