First Principles Study On The Structures,electronic Structures And Optical Prope Rties Of Germanium Vacancy Color Center In Diamond

Quantum information technology has developed rapidly as a new technology in recent years,and the research on diamond color center which can be fully used in quantum computing,quantum sensing and quantum communication is also increasing.The line width of diamond color center is narrow,and the fluorescence wavelengths of different diamond color centers are different.The diamond color center measured by experiments has a short excited state life,stable optical properties,small size,and high compatibility with biology.It has been successfully used in quantum secure communication,quantum high sensitivity measurement and so on.In order to develop and utilize the diamond color center to the maximum extent,it is very important to find a new diamond color center in line with the application of high-quality quantum information technology and to develop the electronic structures and optical properties of the diamond color center.The research of diamond color center provides the basic support for the application of quantum information technology.The research of diamond color center has become an important breakthrough of quantum information technology.The first principle calculation method is used to study the structure,electronic structures and optical properties of diamond germanium vacancy color center in this paper.The stable structure of germanium atom is that germanium atom is in the center of double vacancies.The results of charge density and differential charge density analysis show that germanium atoms are stable in the system,and germanium atoms are bonded with six carbon atoms close to diamond.The band structure and energy level structure of the diamond germanium vacancy color center are analyzed.It is known that the band structure of the diamond germanium vacancy color center is P-type semiconductor.It is found that in P-type semiconductor,doping of the same main group will cause the impurity band to sink to the valence band.The color center of germanium vacancy in diamond is a three-level structure,and the zero phonon line is 614 nm.Its fluorescence wavelength is in the range of visible lightIn order to further explore the influencing factors of the color center properties of diamond germanium vacancy,this paper fully considers the environmental induced variables when the color center of diamond germanium vacancy is formed,and explores whether the color center of diamond germanium vacancy has better properties under the influence of variables,so as to apply it in actual production.In this paper,we take the number of vacancies and nitrogen doping as variables,fully study the influence of the number of vacancies and nitrogen doping on the color center of germanium vacancy,and calculate the electronic structure of the optimal configuration.It is found that the nitrogen element is the favorable doping of the color center of germanium vacancy,and the incorporation of nitrogen element optimizes the energy band and energy level structure of the color center of germanium vacancy,and the optimized zero phonon line is 426nm,within the range of visible light.The optical properties of diamond and diamond germanium vacancy color center are studied by the first principle.The calculated refractive index of diamond is about 2.38,which is consistent with the experimental value.When the photon energy is 0,the reflectivity of diamond is 0.175,and the energy loss coefficient reaches the peak value when the photon energy is 30ev.The refractive index of diamond germanium vacancy color center is about 5.7,which is higher than that of diamond.When the photon energy is 0,the reflectivity of GeV color center is about 0.6,and the energy loss of GeV color center reaches the peak value when the photon energy is 30ev.