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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) Wave functions at the Gamma point of defective ZGNRs. Wave functions at the Gamma point associated with the LUES above the CNP (top Panel) and the HOES below the CNP (bottom Panel) for ZGNR with no defects (a, d), symmetric SW defects (b, e) asymmetric SW defects (c, f). Dark gray (blue online) and light gray (red online) colors correspond to the opposite signs of the wave function.
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Figure 2: (Color online) Wave functions at the Gamma point of defective ZGNRs. Wave functions at the Gamma point associated with the LUES above the CNP (top Panel) and the HOES below the CNP (bottom Panel) for ZGNR with no defects (a, d), symmetric SW defects (b, e) asymmetric SW defects (c, f). Dark gray (blue online) and light gray (red online) colors correspond to the opposite signs of the wave function.

Mentions: Wave functions of electronic states at the Gamma point of the highest-occupied electronic states (HOES) and the lowest-unoccupied electronic states (LUES) are depicted in Figure 2. As expected, the wave functions of the pristine even-index ZGNR at the Gamma-point associated to the HOES and LUES exhibit the well-defined parity with respect to the mirror plane, and their eigenstates in the case of symmetric SW defects, the HOES and LUES, keep the same parity because of the potential induced by the symmetric defects [25,43]. Note that, although the wave functions of both the pristine and symmetric SW defects have well-defined parity, the sign of their wave functions, especially for the electronic states below the CNP, are precisely opposite. For the asymmetric SW defects, the well-defined parity of the wave functions is not preserved. Moreover, the wave function symmetry in this configuration is broken leading to substantial electron backscattering below and above the CNP.


Defect symmetry influence on electronic transport of zigzag nanoribbons.

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

(Color online) Wave functions at the Gamma point of defective ZGNRs. Wave functions at the Gamma point associated with the LUES above the CNP (top Panel) and the HOES below the CNP (bottom Panel) for ZGNR with no defects (a, d), symmetric SW defects (b, e) asymmetric SW defects (c, f). Dark gray (blue online) and light gray (red online) colors correspond to the opposite signs of the wave function.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 2: (Color online) Wave functions at the Gamma point of defective ZGNRs. Wave functions at the Gamma point associated with the LUES above the CNP (top Panel) and the HOES below the CNP (bottom Panel) for ZGNR with no defects (a, d), symmetric SW defects (b, e) asymmetric SW defects (c, f). Dark gray (blue online) and light gray (red online) colors correspond to the opposite signs of the wave function.
Mentions: Wave functions of electronic states at the Gamma point of the highest-occupied electronic states (HOES) and the lowest-unoccupied electronic states (LUES) are depicted in Figure 2. As expected, the wave functions of the pristine even-index ZGNR at the Gamma-point associated to the HOES and LUES exhibit the well-defined parity with respect to the mirror plane, and their eigenstates in the case of symmetric SW defects, the HOES and LUES, keep the same parity because of the potential induced by the symmetric defects [25,43]. Note that, although the wave functions of both the pristine and symmetric SW defects have well-defined parity, the sign of their wave functions, especially for the electronic states below the CNP, are precisely opposite. For the asymmetric SW defects, the well-defined parity of the wave functions is not preserved. Moreover, the wave function symmetry in this configuration is broken leading to substantial electron backscattering below and above the CNP.

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