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dc.contributor.author
Minotti, Fernando Oscar
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dc.contributor.author
Modanese, G.
dc.date.available
2022-12-22T11:05:06Z
dc.date.issued
2021-04
dc.identifier.citation
Minotti, Fernando Oscar; Modanese, G.; Are Current Discontinuities in Molecular Devices Experimentally Observable?; MDPI AG; Symmetry; 13; 4; 4-2021; 1-17
dc.identifier.issn
2073-8994
dc.identifier.uri
http://hdl.handle.net/11336/182108
dc.description.abstract
An ongoing debate in the first-principles description of conduction in molecular devices concerns the correct definition of current in the presence of non-local potentials. If the physical current density j = (−ieh/2m)(Ψ∗∇Ψ − Ψ∇Ψ∗ ) is not locally conserved but can be re-adjusted by a non-local term, which current should be regarded as real? Situations of this kind have been studied for example, for currents in saturated chains of alkanes, silanes and germanes, and in linear carbon wires. We prove that in any case the extended Maxwell equations by Aharonov-Bohm give the e.m. field generated by such currents without any ambiguity. In fact, the wave equations have the same source terms as in Maxwell theory, but the local non-conservation of charge leads to longitudinal radiative contributions of E, as well as to additional transverse radiative terms in both E and B. For an oscillating dipole we show that the radiated electrical field has a longitudinal component proportional to ω ˆP, where ˆP is the anomalous moment∫ Î(x)xd3 x and Î is the space-dependent part of the anomaly I = ∂t ρ + ∇ · j. For example, if a fraction η of a charge q oscillating over a distance 2a lacks a corresponding current, the predicted maximum longitudinal field (along the oscillation axis) is EL,max = 2ηω2 qa/(c2r). In the case of a stationary current in a molecular device, a failure of local current conservation causes a “missing field” effect that can be experimentally observable, especially if its entity depends on the total current; in this case one should observe at a fixed position changes in the ratio B/i in dependence on i, in contrast with the standard Maxwell equations. The missing field effect is confirmed by numerical solutions of the extended equations, which also show the spatial distribution of the non-local term in the current.
dc.format
application/pdf
dc.language.iso
eng
dc.publisher
MDPI AG
dc.rights
info:eu-repo/semantics/restrictedAccess
dc.rights.uri
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
dc.subject
EXTENDED AHARONOV-BOHM ELECTRODYNAMICS
dc.subject
LOCAL CONSERVATION LAWS
dc.subject
QUANTUM TRANSPORT
dc.subject
SCHRÖDINGER EQUATION WITH NON-LOCAL POTENTIAL
dc.subject.classification
Física de Partículas y Campos
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dc.subject.classification
Ciencias Físicas
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dc.subject.classification
CIENCIAS NATURALES Y EXACTAS
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dc.title
Are Current Discontinuities in Molecular Devices Experimentally Observable?
dc.type
info:eu-repo/semantics/article
dc.type
info:ar-repo/semantics/artículo
dc.type
info:eu-repo/semantics/publishedVersion
dc.date.updated
2022-09-20T15:51:54Z
dc.journal.volume
13
dc.journal.number
4
dc.journal.pagination
1-17
dc.journal.pais
Suiza
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dc.description.fil
Fil: Minotti, Fernando Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física del Plasma. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física del Plasma; Argentina
dc.description.fil
Fil: Modanese, G.. Free University of Bozen-Bolzano; Italia
dc.journal.title
Symmetry
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/url/https://www.mdpi.com/2073-8994/13/4/691
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/doi/http://dx.doi.org/10.3390/sym13040691
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