a hexagonal graphite b rhombohedral graphite c simple

(a). hexagonal graphite (b). rhombohedral graphite (c). simple hexagonal graphite (d). cubic diamond (e). hexagonal diamond Polymorphism : 結晶多形

・All atoms are directly above each other A layer in the adjacent planes A layer

A layer ・Half of the atoms are. B directly layer located just above each other in A layer adjacent planes. B layer ・the other half are directly above the centers of the hexagonal rings in the adjacent plane.

A layer ・Half of the atoms are. B directly layer above atoms in the adjacent plane C layer and directly below the centers of the hexagonal rings. A layer B layer ・the other half are directly below atoms and above the ring centers.

・Atomic position in the unit cell is that ( 0 0 0) ( ¼ ¼ ¼) Lattice parameter = 3. 56 Å Energy gap = 5. 47 (e. V)

・Lonsdaleite is obtained from simple hexagonal graphite by decreasing the interlayer distance and by buckling the hexagonal rings. Lonsdaleite：ロンズデーライト

H. Nakayama and H. Katayama-Yoshida(J. Phys : Condens. Matter 15 R 1077 (2003) Graphite Electronic excited states Diamond

J. Kanasaki, E. Inami, K. Tanimura, H. Ohnishi, and K. Nasu(10. 1103/Phys. Rev. Lett. 102. 087402) Structural change occurs

He B 5 C 6 N 7 O 8 F 9 2 10 Ne - to propose a new method to fabricate c-BN

He B 5 C 6 N 7 O 8 F 9 2 10 Ne propose a new method to fabricate c-BN

Properties of BNs Applications Heatsink : 放熱板　 Grinding : 研磨

He B 5 C 6 N 7 O 8 F 9 2 10 Ne propose a new method to fabricate c-BN

Ab-initio Calculation package : Quantum espresso-4. 2. 1

Basis Core States ○ PW Not Considered ◎ PW+SW Considered Time Accuracy p. p. (pseudo potential) ◎ FLAPW △ PW : Plane Wave SW : Spherical Wave

Ａ The View From (0 0 1) with hexagonal axis A layer Ｃ B layer C layer ＢＡ A layer

Rhombohedral (R/c = 0. 33) Zinc-Blende (R/c = 0. 25)

cosα = 0. 5 lattice parameter = 4. 85

H. Funashima, private communication (2011)

2 π sp band H. Funashima, private communication (2011)

Total energy relative to the non- doping BNs 0. 4 Hole concentration per atom 0. 2 0 0. 25 0. 26 0. 27 0. 28 0. 29 0. 31 0. 32 0. 33 non-doping 0. 01 -0. 2 Energy [e. V/atom] 0. 02 0. 03 -0. 4 0. 05 -0. 6 0. 07 0. 08 -0. 8 0. 09 -1 -1. 2 at 0. 08/atom, The activation energy vanishes 0. 11 0. 12 0. 13 -1. 4 -1. 6 Zinc-blende R/c Rhombohedral

BN non-doping 0. 3 total energy (e. V) 0. 25 0. 2 0. 15 0. 1 0. 05 0 0. 25 0. 26 0. 27 0. 28 0. 29 R/c 0. 31 0. 32 0. 33

0. 33→ 0. 50

BN non-doping 0. 3 total energy (e. V) 0. 25 Metastable ? ! 0. 2 0. 15 0. 1 0. 05 0 0. 25 0. 26 0. 27 0. 28 0. 29 R/c 0. 31 0. 32 0. 33