Highly correlated electronic state in a ferrimagnetic quadruple perovskite CuCu$_3$Fe$_2$Re$_2$O$_{12}$

Abstract: Recently synthesized quadruple perovskite CuCu$3$Fe$_2$Re$_2$O${12}$ possesses strong ferromagnetism and unusual electron properties, including enhanced electronic specific heat. Application of the first principles electronic structure approaches unambiguously shows importance of the many-body effects in this compound. While CuCu$3$Fe$_2$Re$_2$O${12}$ is half-metallic ferrimagnet in the DFT+U method, in the density functional theory (DFT) combined with the dynamical mean-field theory (DMFT) it appears to be a metal. Strong correlations lead to a renormalization of electronic spectrum and formation of incoherent states close to the Fermi level. Electronic specific heat and magnetic properties obtained in the DFT+DMFT approach are in better agreement with available experimental data than derived by other band structure techniques.