Orbital non-fermi-liquid behavior in cubic ruthenates

Area of Science:

• Condensed matter physics
• Materials science
• Quantum mechanics

Background:

• Ruthenates exhibit complex electronic properties, including anomalous conductivity and magnetic behavior.
• Understanding these phenomena is crucial for developing novel electronic materials.

Purpose of the Study:

• To investigate the anomalous physical responses of cubic ruthenates, specifically SrRuO3 and CaRuO3.
• To explain the observed power-law conductivity, Raman line shapes, and Hall currents.
• To introduce a theoretical framework describing these exotic electronic states.

Main Methods:

• Analysis of anomalous physical responses: fractional power-law conductivity, anomalous Raman line shapes, and Hall currents.
• Development of a multiorbital, correlated model.
• Application of dynamical mean-field theory (DMFT) to the model.

Main Results:

• Identification of a new, local (orbital) non-Fermi-liquid state.
• Explanation of power-law observations through strong, multiorbital Coulomb interactions.
• Prediction of two distinct relaxation rates for transport, matching experimental data.

Conclusions:

• The proposed non-Fermi-liquid state provides a unified explanation for the anomalous properties of ruthenates.
• Dynamical mean-field theory is a powerful tool for understanding strongly correlated electron systems.
• The findings offer insights into the fundamental physics of exotic electronic states in materials.