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Defect symmetry influence on electronic transport of zigzag nanoribbons.

Zeng H, Leburton JP, Xu Y, Wei J - Nanoscale Res Lett (2011)

Bottom Line: The wave function of asymmetric SW configuration is very similar to that of the pristine GNR, except for the defective regions.Unexpectedly, calculations predict that the asymmetric SW defects are more favorable to electronic transport than the symmetric defects configuration.These distinct transport behaviors are caused by the different couplings between the conducting subbands influenced by wave function alterations around the charge neutrality point.

View Article: PubMed Central - HTML - PubMed

Affiliation: College of Physical Science and Technology, Yangtze University, Jingzhou, Hubei 434023, China. zenghui@yangtzeu.edu.cn.

ABSTRACT
The electronic transport of zigzag-edged graphene nanoribbon (ZGNR) with local Stone-Wales (SW) defects is systematically investigated by first principles calculations. While both symmetric and asymmetric SW defects give rise to complete electron backscattering region, the well-defined parity of the wave functions in symmetric SW defects configuration is preserved. Its signs are changed for the highest-occupied electronic states, leading to the absence of the first conducting plateau. The wave function of asymmetric SW configuration is very similar to that of the pristine GNR, except for the defective regions. Unexpectedly, calculations predict that the asymmetric SW defects are more favorable to electronic transport than the symmetric defects configuration. These distinct transport behaviors are caused by the different couplings between the conducting subbands influenced by wave function alterations around the charge neutrality point.

No MeSH data available.


Related in: MedlinePlus

(Color online) Schematics of the molecular device considered in the calculation of ZGNR. The whole device is composed of scattering region and two electrodes containing the corresponding pristine ZGNRs. The SW defects are highlighted by yellow atoms (a) ZGNR with symmetric SW defects, some C-C bond lengths and angles are shown by (c); (b) ZGNR with asymmetric SW defects, while some C-C bond lengths and angles are shown by (d).
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Figure 1: (Color online) Schematics of the molecular device considered in the calculation of ZGNR. The whole device is composed of scattering region and two electrodes containing the corresponding pristine ZGNRs. The SW defects are highlighted by yellow atoms (a) ZGNR with symmetric SW defects, some C-C bond lengths and angles are shown by (c); (b) ZGNR with asymmetric SW defects, while some C-C bond lengths and angles are shown by (d).

Mentions: The electronic transport properties of the nanoribbon device have been performed by using non-equilibrium Green's function (NEGF) methodology [40,41]. In order to self-consistently calculate the electrical properties of nanodevices, we construct the two-probe device geometry where the central region contains the SW defects and both leads consist each of the two supercell pristine ZGNR, as shown in Figure 1. The equilibrium conductance G is obtained from the Landauer formula such that G = G0T (E), where G0 is the quantum conductance with relationship . The transmission coefficient T as a function of the electron energy E is given by(1)


Defect symmetry influence on electronic transport of zigzag nanoribbons.

Zeng H, Leburton JP, Xu Y, Wei J - Nanoscale Res Lett (2011)

(Color online) Schematics of the molecular device considered in the calculation of ZGNR. The whole device is composed of scattering region and two electrodes containing the corresponding pristine ZGNRs. The SW defects are highlighted by yellow atoms (a) ZGNR with symmetric SW defects, some C-C bond lengths and angles are shown by (c); (b) ZGNR with asymmetric SW defects, while some C-C bond lengths and angles are shown by (d).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211316&req=5

Figure 1: (Color online) Schematics of the molecular device considered in the calculation of ZGNR. The whole device is composed of scattering region and two electrodes containing the corresponding pristine ZGNRs. The SW defects are highlighted by yellow atoms (a) ZGNR with symmetric SW defects, some C-C bond lengths and angles are shown by (c); (b) ZGNR with asymmetric SW defects, while some C-C bond lengths and angles are shown by (d).
Mentions: The electronic transport properties of the nanoribbon device have been performed by using non-equilibrium Green's function (NEGF) methodology [40,41]. In order to self-consistently calculate the electrical properties of nanodevices, we construct the two-probe device geometry where the central region contains the SW defects and both leads consist each of the two supercell pristine ZGNR, as shown in Figure 1. The equilibrium conductance G is obtained from the Landauer formula such that G = G0T (E), where G0 is the quantum conductance with relationship . The transmission coefficient T as a function of the electron energy E is given by(1)

Bottom Line: The wave function of asymmetric SW configuration is very similar to that of the pristine GNR, except for the defective regions.Unexpectedly, calculations predict that the asymmetric SW defects are more favorable to electronic transport than the symmetric defects configuration.These distinct transport behaviors are caused by the different couplings between the conducting subbands influenced by wave function alterations around the charge neutrality point.

View Article: PubMed Central - HTML - PubMed

Affiliation: College of Physical Science and Technology, Yangtze University, Jingzhou, Hubei 434023, China. zenghui@yangtzeu.edu.cn.

ABSTRACT
The electronic transport of zigzag-edged graphene nanoribbon (ZGNR) with local Stone-Wales (SW) defects is systematically investigated by first principles calculations. While both symmetric and asymmetric SW defects give rise to complete electron backscattering region, the well-defined parity of the wave functions in symmetric SW defects configuration is preserved. Its signs are changed for the highest-occupied electronic states, leading to the absence of the first conducting plateau. The wave function of asymmetric SW configuration is very similar to that of the pristine GNR, except for the defective regions. Unexpectedly, calculations predict that the asymmetric SW defects are more favorable to electronic transport than the symmetric defects configuration. These distinct transport behaviors are caused by the different couplings between the conducting subbands influenced by wave function alterations around the charge neutrality point.

No MeSH data available.


Related in: MedlinePlus