By means of standard and hybrid density functional theory, we analyzed the electronic, optical, and mechanical properties of the two discovered superhard orthorhombic (W) and monoclinic (M) phases of carbon, synthesized by cold compression. We demonstrated that both phases exhibit a transparent insulating behaviour with indirect band gaps of about 5.4 eV (W) and 4.5 eV (M), and highly isotropic optical spectra, substantially different to those of the related body centered tetragonal C4 phase. The analysis of the elastic constants and Vickers hardness confirmed that these phases are as hard as the second hardest material c-BC2N.
REFERENCES
1.
R. B.
Aust
and H. G.
Drickamer
, Science
140
, 817
(1963
).2.
F. P.
Bundy
and J. S.
Kasper
, J. Chem. Phys.
46
, 3437
(1967
).3.
R.
Clarke
and C.
Uher
, Adv. Phys.
33
, 469
(1984
).4.
F. P.
Bundy
et al., Carbon
34
, 141
(1996
).5.
T.
Irifune
et al., Nature (London)
421
, 599
(2003
).6.
H.
Sumiya
and T.
Irifune
, J. Mater. Res.
22
, 2345
(2007
).7.
W. L.
Mao
et al., Science
302
, 425
(2003
).8.
M.
Hanfland
and K.
Syassen
, Phys. Rev. B
40
, 1951
(1989
).9.
10.
M.
Hanfland
et al., Phys. Rev. B
39
, 12598
(1989
).11.
12.
Z.
Wang
et al., Proc. Natl. Acad. Sci. U.S.A.
101
, 13699
(2004
).13.
F. L.
Ribeiro
et al., Phys. Rev. B
72
, 214109
(2005
).14.
F. L.
Ribeiro
et al., Phys. Rev. B
74
, 172101
(2006
).15.
16.
Q.
Li
et al., Phys. Rev. Lett.
102
, 175506
(2009
).17.
K.
Umemoto
et al., Phys. Rev. Lett.
104
, 125504
(2010
).18.
J.-T.
Wang
et al., Phys. Rev. Lett.
106
, 075501
(2011
).19.
R. H.
Baughman
and D. S.
Galvo
, Chem. Phys. Lett.
211
, 110
(1993
).20.
R. H.
Baughman
et al., Synth. Met.
86
, 2371
(1997
).21.
22.
X.-F.
Zhou
et al., Phys. Rev. B
82
, 134126
(2010
).23.
P. Y.
Wei
et al., Appl. Phys. Lett.
97
, 061910
(2010
).24.
A. V.
Krukau
et al., J. Chem. Phys.
125
, 224106
(2006
).25.
G.
Kresse
and J.
Furthmüller
, Phys. Rev. B
54
, 11169
(1996
).26.
G.
Kresse
and J.
Furthmüller
, Comput. Mat. Sci.
6
, 15
(1996
).27.
M.
Gajdoš
, K.
Hummer
, and G.
Kresse
, Phys. Rev. B
73
, 045112
(2006
).28.
P.
Söderlind
and J. E.
Klepeis
, Phys. Rev. B
79
, 104110
(2009
).29.
D. M.
Teter
and R. J.
Hemley
, Science
271
, 53
(1996
).30.
31.
X.-Q.
Chen
et al., Phys. Rev. B
77
, 064103
(2008
).32.
A.
Šimůnek
and J.
Vackář
, Phys. Rev. Lett.
96
, 085501
(2006
).© 2011 American Institute of Physics.
2011
American Institute of Physics
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