[1] Yan M F and Rhodes W W 1981 Grain boundaries in
Semiconductors ed Leamy H J, Pike G E and Seager C H (New York:
North-Holland)

[2] Koudriachova M V et al %, Harrison N M and de Leeuw S W
2001 Phys. Rev.
Lett. 86 1275

[3] Ostermann D et al %, Walther G and Schierbaum K D
2005 Phys. Rev. B
71 235416

[4] Glassford K M and Chelikowsky J R 1992 Phys. Rev. B 46 1284

[5] Muscat J, Swamy V and Harrison N M 2002 Phys. Rev. B 65
224112

[6] Isaak D G et al %, Carnes J D, Anderson O L and Cynn H
1998 Phys. Chem.
Minerals 26 31

[7] Hammer B et al %, Hansen L B and Norskov J K
1999 Phys. Rev. B
59 7413

[8] Vosko S H, Wilk L and Nusair M 1980 Can. J. Phys. 58 1200

[9] Monkhorst H J and Pack J D 1976 Phys. Rev. B 13 5188

[10] Payne M C et al %, Teter M P, Allen D C, Arias T A and Joannopoulos J D
1992 Rev. Mod. Phys. 64 1045

[11] Milan V et al %, Winker B, White J A, Packard C J, Payne M C, Akhmatskaya
%E V and Nobes R H
2002 Int. J. Quantum Chem. 77 895

[12] Murnaghan F D and Acad P N 1944 Proc. Natl. Acad. Sci.
USA 30 244

[13]Reinhardt P, Hess B A and Causa M 1996 Int. J. Quantum
Chem. 58 297

[14] Lindan P J D et al %, Harrison N M, Gillan M J and White J A
1997 Phys. Rev. B 55 15919

[15] Rosciszewski K et al %, Doll K, Paulus B, Fulde P and Stoll H
1998 Phys. Rev. B 57 14667

[16]Cho E and Han S 2006 Phys. Rev. B 73 193202

[17]Burdett J K et al %, Hughbanks T, Miller G J, Richardson J W
%and Smith J V
1987 J. Am. Chem. Soc. 109 3639

[18] Gerward L and Olsen J S 1997 J. Appl. Crystallogr. 30 259

[19] Blanco M A, Francisco E and Luana V 2004 Comput. Phys.
Commun. 158 57

[20] Ogata S, Lyetomi H and Tsurata K 1999 J. Appl. Phys. 86 6

[21] Swamy V and Gale J D 2000 Phys. Rev. B 62 9

[22] Manghnani M H 1969 J. Geophys. Res. 74 4317

[23] Steinle-Neumann G and Stixrude L and Cohen R E 1999
Phys. Rev. B 60 791

[24] Voigt W 1928 Lehrbuch der Kristallphysik (Leipzig: Taubner)

[25] Reuss A 1929 Z. Angew. Math. Mech. 9 55

[26] Hill R 1952 Proc. R. Soc. London A 65 350

[27] Anderson O L 1963 J. Phys. Chem. Solids 24 909

[28] Pascual J et al %, Camassel J and Mathieu H
1978 Phys. Rev. B 18
5606

[29] Poumelec B et al %, Durham P Jand Guo G Y
1991 J. Phys.
Condens. Matter 3 8195

[30] Mo S Dand Ching W Y 1994 Phys. Rev. B 51 19