Theoretical Study of Gallium Nitride Crystal Growth Reaction Mechanism

Abstract

In this work, we investigate GaN(0001) crystal growth focusing on gas-phase and surface reactions from the viewpoint of metalorganic chemical vapor deposition (MOCVD) by ab initio calculations. We consider the adsorption of compounds of Ga and N atoms on a Ga-covered surface cluster model. For the adsorption of these compounds, it is found that Ga–Ga bonds undesirable for the steady growth appear for alkylgallium with amino group, and the compounds which have coordinate bonds with NH3 can be a solution for this problem, since they do not make Ga–Ga bonds.

Theoretical study of lithium ionic conductors by electronic stress tensor density and electronic kinetic energy density

“…In order for efficient material search, it is important to characterize the chemical bonding of the lithium ionic conductors through the quantum chemical electronic structure calculation, and establish the connection with their material properties like chemical stability, diffusivity, and so on. We have been developing the characterization scheme of electronic structure using the electronic stress tensor density and kinetic energy density based on the rigged quantum electrodynamics (RQED) theory, and have applied it to various quantum systems . As a preliminary stage of our research, we have applied our method to the crystal structures of and .…”

“…Actually, as will be shown below, the stress tensor alone is not sufficient to characterize the ionicity and we need to see the pattern of the electronic kinetic energy density. Our definition of the kinetic energy density is not positive‐definite and there exist zero surfaces, which are designated as “electronic interfaces.” The outermost electronic interface can give a clear image of the intrinsic shape of atoms and molecules, and it has been used to investigate various chemical reactions in our past works . To characterize ionicity, the electronic interface is found to play an important role.…”

“…[3] The outermost electronic interface can give a clear image of the intrinsic shape of atoms and molecules, and it has been used to investigate various chemical reactions in our past works. [8][9][10][11][12][13][14][16][17][18]21,22,26,[30][31][32][33][34] To characterize ionicity, the electronic interface is found to play an important role.…”

Theoretical study of atoms by the electronic kinetic energy density and stress tensor density

“…In order to understand the quantum systems from the viewpoint of quantum field theory, in particular quantum electrodynamics (QED), one of the authors has developed the rigged QED (RQED) theory and our group has applied it to various molecular and condensed matter systems. Due to the field theoretic nature, the theory has local quantities defined at each point in space which are useful to describe quantum systems. Most important quantities are the electronic kinetic energy density and stress tensor density, whose definitions and meanings are presented in the next section.…”

“…, and a variety of chemical reactions has been studied using it. We briefly describe some of them below. In Ref.…”