First Principles Calculation of Magnetic Resonance Properties of Cu2-δX (X = Se, S, Te)

In order to have a better understanding of the electronic structures and physical properties of Cu2-δX (X = Se, S, Te) copper chalcogenides. First principles were performed to calculate the chemical shift, band structure, and electron density of states of Cu2-δX (X = Se, S, Te). By comparing our calculation results with previous experimental works, we found that the predicted electronic structures of Cu2Se, Cu2Te and Cu2S transform from semimetal to semiconductor after adding on-site Coulomb U, which reflects the real properties of the materials. By using (Density Functional Theory) DFT + U method, the calculation result is close to the real electronic structure. The calculation result of chemical shift of adding U does not reach the ideal expectation, and the reason is not clear at present. In this paper, the theoretical electronic structures of Cu2Se, Cu2Te and Cu2S are better calculated by DFT + U method and compared with the actual properties. The effect of Cu-s electron on the chemical shift is understood, and a theoretical result of the chemical shift is calculated, which provides a powerful reference for the subsequent research and understanding of the electronic structure and physical properties of the compounds with S groups of Cu.