Valence and orbital states of rare earth Heavy Fermion compounds close to the quantum critical point: Resonant and non-resonant inelastic X-ray scattering investigations.

• Applicant: Dr. Andrea Severing
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2013 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 223392744

In the very rich temperature-pressure-magnetic field-substitution phase diagram Heavy Fermion systems display a wealth of fascinating phenomena such as quantum criticality and unconventional superconductivity with magnetism lying close by. Heavy Fermion properties are governed by the delicate balance of the strong coulomb repulsion between the electrons of the f shell and the hybridization between f and conduction electrons, so that electronic properties such as occupancy nf of the f states, energy scales determined by the Kondo temperature TK, and the wave functions of the Hund's rule ground state are key parameters to model these phase properties. Here we propose a systematic investigation of these key parameters in the vicinity of the quantum critical point by spectroscopic means. The availability of high-brilliance third generation synchrotron sources makes electron spectroscopies as resonant and non-resonant inelastic x-ray scattering (RIXS, NRIXS) under extreme conditions possible.

• DFG Programme: Research Grants
• Participating Person: Dr. Thomas Willers