First-Principles Study of BN, SiC, and AlN Polytypes

Comprehensive Study on Band-Gap Variations insp3-Bonded Semiconductors: Roles of Electronic States Floating in Internal Space

“…The materials with dominantly ionicity prefer hexagonal structure. SiC is a exquisite material possessing a delicate balance of ionicity and covalency to exhibit hundreds of polytypes [30]. As for the other materials, most stable structure of each material is 2H-AlN, 2H-BN, 2H-GaN, 3C-Si, and 3C-C, respectively.…”

First-Principles Study of 30H-BN Polytypes

“…We have investigated the electronic and lattice properties of 2H-$6H-BN(AlN, SiC) 11,12) and 10H-BN(AlN), 13) and 12H-BN. 14) 2H$5H polytypes have unique structure, respectively.…”

“…Hexagonality is the ratio of the number of h character and the total number of c and h characters in the unit cell. 12) 10H and 12H polytypes have 18 and 58 structures, 15) respectively. In contrast, the 30H polytype has over 6000000 structures whose stacking sequences are different from each other, 15) and possible crystal symmetries and hexagonalities (H[%]) are P6 3 mc and P3m1, and 6.7%, 13.3%, 20%, 26.7%, 33.3%, 40%, 46.7%, 53.3%, 60%, 66.7%, 73.3%, 80%, 86.7%, and 93.3%, respectively.…”

“…Notations are the ABC notation. We From the previous studies, 12,13) the total energies of BN and AlN polytypes have a relation to hexagonality (H). This is an important parameter to discuss the stabilities of BN and AlN polytypes.…”

“…This is an important parameter to discuss the stabilities of BN and AlN polytypes. 12,13) Energetical stabilities of BN and AlN polytypes are described by the number (N third ) of third-neighbor cation-anion pairs in the unit cell. A ratio of N third and p corresponds to hexagonality.…”