Controlling local currents in molecular junctions

Yadalam, Hari Kumar; Harbola, Upendra

doi:10.1103/physrevb.94.115424

Cited by 9 publications

(9 citation statements)

References 28 publications

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“…Each contribution characterizes electron population exchange with a bath (contact) and/or redistribution in energy due to corresponding interaction. For example, source term due to electron-vibration interaction, P vib , is obtained by substituting self-energy (17) in place of the total self-energy in (13) (see Eq. (C1) in Appendix C).…”

Section: Turementioning

confidence: 99%

On simulation of local fluxes in molecular junctions

Cabra

Jensen

Galperin

2018

The Journal of Chemical Physics

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We present a pedagogical review of the current density simulation in molecular junction models indicating its advantages and deficiencies in analysis of local junction transport characteristics. In particular, we argue that current density is a universal tool which provides more information than traditionally simulated bond currents, especially when discussing inelastic processes. However, current density simulations are sensitive to the choice of basis and electronic structure method. We note that while discussing the local current conservation in junctions, one has to account for the source term caused by the open character of the system and intra-molecular interactions. Our considerations are illustrated with numerical simulations of a benzenedithiol molecular junction.

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Section: Turementioning

confidence: 99%

On simulation of local fluxes in molecular junctions

Cabra

Jensen

Galperin

2018

The Journal of Chemical Physics

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“…The Green's functions obtained by solving equation of motion [48] in energy domain can be used in Eq. ( 3) to get expression for the net current, I L [16,49].…”

Section: Model Hamiltonian and Current Calculationmentioning

confidence: 99%

Current in nanojunctions: Effects of reservoir coupling

Yadalam

Harbola

2018

Physica E: Low-dimensional Systems and Nanostructures

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We study the effect of system reservoir coupling on currents flowing through quantum junctions. We consider two simple doublequantum dot configurations coupled to two external fermionic reservoirs and study the net current flowing between the two reservoirs. The net current is partitioned into currents carried by the eigenstates of the system and by the coherences between the eigenstates induced due to coupling with the reservoirs. We find that current carried by populations is always positive whereas current carried by coherences are negative for large couplings. This results in a non-monotonic dependence of the net current on the coupling strength. We find that in certain cases, the net current can vanish at large couplings due to cancellation between currents carried by the eigenstates and by the coherences. These results provide new insights into the non-trivial role of system-reservoir couplings on electron transport through quantum dot junctions. In the presence of weak coulomb interactions, net current as a function of system reservoir coupling strength shows similar trends as for the non-interacting case.

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“…Due to the presence of this gauge field the system shows persistent currents, which corresponds to the generation of a spontaneous current as a response to changes in magnetic flux. Persistent currents have been well studied both experimentally and theoretically, [23][24][25][26] focusing on magnification, [27] controlling local currents, [28] currents in 1D disordered rings, [29] electron correlations, [30] and even in alternative ways to generate persistent currents without a magnetic flux. [31] Furthermore, persistent currents are sensitive to external perturbations, any change that makes variations in the spectra of a determinated system will be observed in the persistent current.…”

Section: Introductionmentioning

confidence: 99%

Influence of Majorana Bound States in Quantum Rings

et al. 2020

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A quantum ring coupled to a 1D topological superconductor hosting Majorana bound states (MBSs) is investigated. The MBSs effects over the spectrum and persistent current along the quantum ring are studied. The spectra of the system are obtained by an exact numerical diagonalization of the Bogoliubov‐de Gennes Hamiltonian in the Majorana representation. In addition, Green's function formalism is implemented for analytical calculations and obtained a switching condition in the MBSs fermionic parity. Three different patterns that could be obtained for the spatial separation of the MBSs, named: bowtie, diamond, and asymmetric, are reported here, which are present only in odd parity in the quantum ring, while only a single pattern (bowtie) is obtained for even parity. Those patterns are subject strictly to the switching condition for the MBSs. Besides, quantum ring with the presence of a Majorana zero mode presents gapped/gapless spectra in odd/even parity showing in the even case a subtle signature in the persistent current.

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Controlling local currents in molecular junctions

Cited by 9 publications

References 28 publications

On simulation of local fluxes in molecular junctions

On simulation of local fluxes in molecular junctions

Current in nanojunctions: Effects of reservoir coupling

Influence of Majorana Bound States in Quantum Rings

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