The role of correlations in the high-pressure phase of FeSe

We present a systematic study of the high-pressure FeSe phase performed by means of the first-principle electronic structure calculations. Basing on available experimental information about the unit cell geometry we calculate the band structure and characterize the related properties during their pressure driven evolution. The electronic structure including the hybrid functional B3LYP or the Hubbard parameter U for the iron d states lead to the correct semiconducting ground state for the hexagonal stoichiometric FeSe within the broad pressure range (up to 30 GPa).