A new carbon modification having a face-centred cubic (fcc) structure has b
een obtained as a result of the transformation of a diamond surface during
treatment in hydrogen plasma. The calculated density of electronic states o
f the fee carbon phase provides evidence that it is a metallic form of carb
on. The experimentally obtained crystal lattice parameter of the fee carbon
phase is found to be 0.3563 nm, which is close to that computed by the lin
ear combination of atomic orbitals (LCAO) method. The fee carbon phase has
a characteristic edge offset in the electron energy loss spectrum distingui
shing it from diamond, amorphous carbon and graphite. Here we show for the
first time clear evidence for the existence of a carbon phase with the fee
crystal structure. (C) 2001 Elsevier Science B.V. All rights reserved.