First Principles Study Of Electronic Structure And Linear Response Functions Of La₂O₃

With the rapid progress and development of computational physics and computational science, the scientific computing domain obtained the more and more, more and more accurate calculation results. Based on first principles calculation under the framework of density functional theory has been adopted by more and more scientific research workers, and make as a research method, which is independent of the experimental study and the theoretical research. ABINIT package is just one kind of many programs, it has the advantages of open source programs. Through the continued developing and perfecting in recent years, on the one hand, it can be run in parallel in the compute cluster which significantly enhance calculation efficiency; On the other hand it can be simulated more physical properties of materials by optimizing the algorithm, and can be ensure good accuracy and reliability.In ABINIT applications, it uses the plane wave pseudo potential method to expand the electron wave function of system. Real electronic wave function will exist the singularity and intense oscillation in the area of the closer to the nucleus, this makes plane wave vector’s quantity which expand an electronic wave function is huge, this will affect the precision and computational efficiency of program running, seriously. This article uses the OPIUM program generated the calculation potential, and further reduce the number of plane wave in order to improve the accuracy of calculation. According to the results, the generated pseudo potential in this paper, can save a large number of computing time and computing resources, if it satisfies the calculation accuracy.La2O3as a kind of typical rare earth oxides, it has the advantages of high dielectric constant and wide band gap, and it has good thermal stability between Si and La2O3, so, it is expected to become the new generation of gate dielectric materials. But the reach of La2O3electronic structure and properties of linear response function, etc, is relatively lack, so this paper adopts the method of first principles calculations to research. On the basis of the optimization of geometrical structure in La2O3, we calculated band structure, electron structure, Born effective charge tensor, dielectric function tensor, elastic tensor, compliance tensor, thermodynamic and optical properties, etc. with density functional perturbation theory. Compared with other experimental or calculated data, the calculation results of this paper is reliable. It shows that using potential plane wave method based on first principles study of the physical properties of the rare earth oxide is feasible. Because of the lack of experimental data for dielectric function tensor, elastic tensor, compliance tensor and optical properties, so the results of this paper can be used as a reference to experimental and theoretical studies.