Electronic Correlations in Altermagnet MnTe in Hexagonal Crystal Structure.

In this article, we present the results of the first-principles study of altermagnet MnTe crystallized in the hexagonal-type crystal structure. Our theoretical calculations have been performed within density functional theory (DFT) and demonstrated that the altermagnetic phase of MnTe has the lowest total energy corresponding to the stable ground state. The calculations carried out accounting for electronic correlations in DFT+U resulted in significant changes in the electronic structure, as well as magnetic properties of altermagnet MnTe and the increased bandgap. In additional calculations with spin-orbit coupling and electronic correlations (DFT+U+SO), we showed that the bandgap is less than in the DFT+U calculations, but the electronic structure did not change noticeably. In addition, the investigated pressure effects for the compound under study revealed an insulator to metal transition under pressure for the hexagonal-type crystal structure. An experimental finding of a metallic state can be complicated by structural transitions into other phases, not considered in our study, which can occur at high pressures. Experimental measurements for MnTe above 40 GPa are required.