Competition between electronic correlations and hybridization in CaMn$_{2}$Bi$_{2}$

Abstract

We study the interplay between electronic correlations and hybridization in the low-energy electronic structure of CaMn$_2$Bi$_2$, a candidate hybridization-gap semiconductor. Utilizing a DFT+$U$ approach we find both the antiferromagnetic N\'eel order and band gap in good agreement with the corresponding experimental values. We further find that, under hydrostatic pressure, the band gap is mainly governed by magnetic correlations, whereas hybridization has a greater impact on states at higher band energies. This result suggests that CaMn$_2$Bi$_2$ is more closely related to the high-temperature superconducting cuprates and iron pnictides than the heavy fermion class of materials. Finally, we also find the antiferromagnetic CaMn$_2$Bi$_2$ to be topologically trivial for all pressures studied.