Dynamical Correlations and Screened Exchange on the Experimental Bench: Spectral Properties of the Cobalt Pnictide BaCo2As2

Ambroise van Roekeghem; Thomas Ayral; Jan M. Tomczak; Michele Casula; Nan Xu; Hong Ding; Michel Ferrero; Olivier Parcollet; Hong Jiang; Silke Biermann

doi:10.1103/PhysRevLett.113.266403

Dynamical Correlations and Screened Exchange on the Experimental Bench: Spectral Properties of the Cobalt Pnictide BaCo2As2

Ambroise van Roekeghem, Thomas Ayral, Jan M. Tomczak, Michele Casula, Nan Xu, Hong Ding, Michel Ferrero, Olivier Parcollet, Hong Jiang, Silke Biermann

DOI 10.1103/PhysRevLett.113.266403 · Physical Review Letters

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Abstract

Understanding the Fermi surface and low-energy excitations of iron or cobalt pnictides is crucial for assessing electronic instabilities such as magnetic or superconducting states. Here, we propose and implement a new approach to compute the low-energy properties of correlated electron materials, taking into account both screened exchange beyond the local density approximation and local dynamical correlations. The scheme allows us to resolve the puzzle of BaCo2As2, for which standard electronic structure techniques predict a ferromagnetic instability not observed in nature.