148
7 Carbon Allotropes
Fig. 7.1 STM protrusions and STS resonant current probed from a graphite surface atomic vacancies and from b GNR z-edge. c, d DFT derived edge states of asymmetric-dumbbell shaped,
unpaired, and polarized electrons with spin up and down (color difference). The locally densely
entrapped bonding and core electrons polarize and pin the dangling bond electrons [93]. Reprinted
with permission from [43, 105]. Copyright 2010 and 2005 American Physical Society
However, such resonant states are absent from the flat skin, from graphene interior, or
from graphene armchaired edges. The sharpness of the STM images and the resonant
peaks are tip condition and probing temperature sensitive. These observations suggest
that the point defects and the GNR z-edge are naturally the same in terms of bond
relaxation, core electron entrapment, and nonbonding electron polarization [93].
DFT calculations [93] revealed that the DFPs with a high-spin-density create
preferably at the z-edge or at an atomic vacancy of a GNR. The densely entrapped
core electrons polarize the dangling σ-bond electrons of atoms of identical
√
3d
7 Carbon Allotropes
Fig. 7.1 STM protrusions and STS resonant current probed from a graphite surface atomic vacancies and from b GNR z-edge. c, d DFT derived edge states of asymmetric-dumbbell shaped,
unpaired, and polarized electrons with spin up and down (color difference). The locally densely
entrapped bonding and core electrons polarize and pin the dangling bond electrons [93]. Reprinted
with permission from [43, 105]. Copyright 2010 and 2005 American Physical Society
However, such resonant states are absent from the flat skin, from graphene interior, or
from graphene armchaired edges. The sharpness of the STM images and the resonant
peaks are tip condition and probing temperature sensitive. These observations suggest
that the point defects and the GNR z-edge are naturally the same in terms of bond
relaxation, core electron entrapment, and nonbonding electron polarization [93].
DFT calculations [93] revealed that the DFPs with a high-spin-density create
preferably at the z-edge or at an atomic vacancy of a GNR. The densely entrapped
core electrons polarize the dangling σ-bond electrons of atoms of identical
√
3d