Effect of Coulomb Interactions on the Electronic and Magnetic Properties of Two-Dimensional CrSiTe3 and CrGeTe3 Materials
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We investigate the electronic and magnetic structures of two-dimensional transition metal tri-chalcogenide CrSiTe3 and CrGeTe3 materials by carrying out first-principles calculations. The single-layer CrSiTe3 and CrGeTe3 are found to be a ferromagnetic insulator, where the presence of the strong dpσ-hybridization of Cr eg-Te p plays a crucial role for the ferromagnetic coupling between Cr ions. We observe that the bandgaps and the interlayer magnetic order vary notably depending on the magnitude of on-site Coulomb interaction U for Cr d electrons. The bandgaps are formed between the Cr eg conduction bands and the Te p valence bands for both CrSiTe3 and CrGeTe3 in the majority-spin channel. The dominant Te p antibonding character in the valence bands just below the Fermi level is related to the decrease of the bandgap for the increase of U. We elucidate the energy band diagram, which may serve to understand the electronic and magnetic properties of the ABX3-type transition metal tri-chalcogenides in general.
KeywordsTransition metal tri-chalcogenide electronic structure two-dimensional ferromagnetism
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We gratefully acknowledge A. Fujimori and Kee Hoon Kim for valuable discussions. This work was supported by the National Research Foundation of Korea (NRF) (No. 2017R1A2B4007100). JY gratefully acknowledges the support and hospitality provided by the Max Planck Institute for the Physics of Complex Systems, where this work was completed during his visit to the institute.