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Article: First-principles calculation of the Andreev conductance of carbon wires

TitleFirst-principles calculation of the Andreev conductance of carbon wires
Authors
Issue Date2012
PublisherAmerican Physical Society. The Journal's web site is located at http://prb.aps.org/
Citation
Physical Review B (Condensed Matter and Materials Physics), 2012, v. 86 n. 3, article no. 035414, p. 035414-1-035414-5 How to Cite?
AbstractWe developed a first-principles approach based on nonequilibrium Green's function (NEGF) combined with density functional theory (DFT) to investigate quantum transport properties of normal-metal-superconductor (N-S) hybrid systems. As an application of our theory, we investigated the Andreev conductance of atomic wires consisting of 4-15 carbon atoms in contact with one normal Al lead and another superconducting Al lead from first principles. Numerical results show that the Andreev conductance oscillates between an even and odd number of carbon atoms. In the presence of the superconducting lead, the self-consistent scattering potential of the N-S system can be very different from that of the corresponding normal system. Furthermore, a small change of scattering potential can give rise to a significant change of Andreev conductance. For an even number of carbon atoms, the change of scattering potential gives rise to a 4-7% difference in conductance, while when the number of carbon atoms n is odd, a 14-30% change of conductance is observed due to the potential change. We find that the charge transfer plays an important role in N-S systems. For the carbon wire with normal Al contacts, there is a significant charge transfer in real space that is responsible for the even-odd oscillation in conductance. When a superconducting lead is present, the charge is redistributed in momentum space, although it is almost not changed in real space. For even n, a 10% change of charge density at Fermi level is found mainly in the lead region. For odd n, however, the change of charge density at Fermi level is even more than 30% near the first, third, etc., carbon atoms. Since less charge density is available at Fermi level, there is a decrease in conductance for all carbon wires, especially for the wires with odd number of carbon atoms. Our results indicate that the self-consistent calculation of the scattering potential is necessary to obtain an accurate Andreev conductance of N-S hybrid structures. © 2012 American Physical Society.
Persistent Identifierhttp://hdl.handle.net/10722/164495
ISSN
2014 Impact Factor: 3.736
2015 SCImago Journal Rankings: 1.933
ISI Accession Number ID

 

DC FieldValueLanguage
dc.contributor.authorWang, Ben_US
dc.contributor.authorWei, Yen_US
dc.contributor.authorWang, Jen_US
dc.date.accessioned2012-09-20T08:00:34Z-
dc.date.available2012-09-20T08:00:34Z-
dc.date.issued2012en_US
dc.identifier.citationPhysical Review B (Condensed Matter and Materials Physics), 2012, v. 86 n. 3, article no. 035414, p. 035414-1-035414-5en_US
dc.identifier.issn1098-0121-
dc.identifier.urihttp://hdl.handle.net/10722/164495-
dc.description.abstractWe developed a first-principles approach based on nonequilibrium Green's function (NEGF) combined with density functional theory (DFT) to investigate quantum transport properties of normal-metal-superconductor (N-S) hybrid systems. As an application of our theory, we investigated the Andreev conductance of atomic wires consisting of 4-15 carbon atoms in contact with one normal Al lead and another superconducting Al lead from first principles. Numerical results show that the Andreev conductance oscillates between an even and odd number of carbon atoms. In the presence of the superconducting lead, the self-consistent scattering potential of the N-S system can be very different from that of the corresponding normal system. Furthermore, a small change of scattering potential can give rise to a significant change of Andreev conductance. For an even number of carbon atoms, the change of scattering potential gives rise to a 4-7% difference in conductance, while when the number of carbon atoms n is odd, a 14-30% change of conductance is observed due to the potential change. We find that the charge transfer plays an important role in N-S systems. For the carbon wire with normal Al contacts, there is a significant charge transfer in real space that is responsible for the even-odd oscillation in conductance. When a superconducting lead is present, the charge is redistributed in momentum space, although it is almost not changed in real space. For even n, a 10% change of charge density at Fermi level is found mainly in the lead region. For odd n, however, the change of charge density at Fermi level is even more than 30% near the first, third, etc., carbon atoms. Since less charge density is available at Fermi level, there is a decrease in conductance for all carbon wires, especially for the wires with odd number of carbon atoms. Our results indicate that the self-consistent calculation of the scattering potential is necessary to obtain an accurate Andreev conductance of N-S hybrid structures. © 2012 American Physical Society.-
dc.languageengen_US
dc.publisherAmerican Physical Society. The Journal's web site is located at http://prb.aps.org/-
dc.relation.ispartofPhysical Review B (Condensed Matter and Materials Physics)en_US
dc.rightsPhysical Review B (Condensed Matter and Materials Physics). Copyright © American Physical Society.-
dc.rightsCreative Commons: Attribution 3.0 Hong Kong License-
dc.titleFirst-principles calculation of the Andreev conductance of carbon wiresen_US
dc.typeArticleen_US
dc.identifier.emailWang, B: benwb@hku.hken_US
dc.identifier.emailWang, J: jianwang@hku.hken_US
dc.identifier.authorityWang, J=rp00799en_US
dc.description.naturepublished_or_final_version-
dc.identifier.doi10.1103/PhysRevB.86.035414-
dc.identifier.scopuseid_2-s2.0-84863670273-
dc.identifier.hkuros205778en_US
dc.identifier.hkuros210995-
dc.identifier.volume86en_US
dc.identifier.issue3, article no. 035414-
dc.identifier.spage035414-5en_US
dc.identifier.epage035414-1en_US
dc.identifier.isiWOS:000306311500005-
dc.publisher.placeUnited States-

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