摘要
In order to have a better understanding of the electronic structures and physical properties of Cu<sub>2-<span style="white-space:nowrap;"><em>δ</em></span></sub>X (X = Se, S, Te) copper chalcogenides. First principles were performed to calculate the chemical shift, band structure, and electron density of states of Cu<span style="white-space:nowrap;"><sub>2-<em>δ</em></sub></span>X (X = Se, S, Te). By comparing our calculation results with previous experimental works, we found that the predicted electronic structures of Cu<sub>2</sub>Se, Cu<sub>2</sub>Te and Cu<sub>2</sub>S 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 Cu<sub>2</sub>Se, Cu<sub>2</sub>Te and Cu<sub>2</sub>S 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.
In order to have a better understanding of the electronic structures and physical properties of Cu<sub>2-<span style="white-space:nowrap;"><em>δ</em></span></sub>X (X = Se, S, Te) copper chalcogenides. First principles were performed to calculate the chemical shift, band structure, and electron density of states of Cu<span style="white-space:nowrap;"><sub>2-<em>δ</em></sub></span>X (X = Se, S, Te). By comparing our calculation results with previous experimental works, we found that the predicted electronic structures of Cu<sub>2</sub>Se, Cu<sub>2</sub>Te and Cu<sub>2</sub>S 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 Cu<sub>2</sub>Se, Cu<sub>2</sub>Te and Cu<sub>2</sub>S 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.
作者
Zhipeng Shao
Chenglong Shi
Zhipeng Shao;Chenglong Shi(School of Science, University of Shanghai for Science and Technology, Shanghai, China)
