Quantum kinetic description of Coulomb effects in one-dimensional nanoscale transistors

Indlekofer, K. M.; Knoch, J.; Appenzeller, Joerg

doi:10.1103/physrevb.72.125308

Cited by 26 publications

(42 citation statements)

References 32 publications

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“…Referring the interested reader to Ref. [15] for a detailed description of the method it should be pointed out that this approach is a kind of generalization of the standard theories -developed for quantum wires [16,17] -so as to adjust them to CNT systems. One of the noteworthy features of the present model is the way the interface has been modelled.…”

Section: Resultsmentioning

confidence: 99%

Remarks on theoretical modelling of spin-dependent electronic transport in carbon nanotubes and graphene

Krompiewski

2011

Open Physics

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Abstract:This contribution reports on charge and spin transport through graphene nanoribbons (GrNs) and carbon nanotubes (CNTs). The paper focuses on the giant magnetoresistance effect in these materials, and their potential usefulness for spintronic applications. As examples, the following devices are shortly discussed: GrNs in the ballistic transport regime, a CNT-based Schottky-barrier field effect transistor (CNT SB-FET), as well as CNT quantum dots in the Coulomb blockade limit.

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Section: Resultsmentioning

confidence: 99%

Remarks on theoretical modelling of spin-dependent electronic transport in carbon nanotubes and graphene

Krompiewski

2011

Open Physics

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“…One has to note that each gate finger detects a spatially averaged signal within an effective interval l G eff Ӎ l G +2, where l G denotes the geometrical length of the gate segment and the gate screening length. 8 Parasitic stray capacitances which will likely occur in an experimental realization of such a device are not considered in this paper. For the experimental case it might be advantageous to employ alternating screening and signal gates, combined with an optimized THz layout and a suitable preamplification setup for the detection of the image charge signal.…”

Section: B Spatially Resolved Thz Responsementioning

confidence: 99%

“…As a prototype system, one-dimensional nanowire-based structures [3][4][5] have recently attracted great interest due to their advantageous electrostatics and transport properties. [6][7][8] From a different perspective, they also represent model systems for the study of technological as well as physical challenges in future nanodevice designs.…”

Section: Introductionmentioning

confidence: 99%

“…Nevertheless, these relevant degrees of freedom and their associated effective parameters in general are nonlinear functions of the actual experimentally accessible parameters ͑such as gate voltages͒ and not known a priori. In order to address this problem, we have recently introduced a multiconfigurational approach 8,13,14 ͑MCSCG͒ which employs a reduced adaptive basis for the simulation of stationary Coulomb blockade effects in gated nanowire structures.…”

Section: Introductionmentioning

confidence: 99%

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Many-body approach to the terahertz response of Wigner molecules in gated nanowire structures

2008

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In this article, we describe a numerical many-body approach for the description of the electromagnetic response of discrete one-dimensional electronic nanosystems. This approach is based on a recursive method to construct a subset of relevant Slater determinants as a many-body basis for the considered system. In turn, we employ a generalized Floquet theory to calculate the periodic many-body statistical operator for the system which is subject to a periodic time-dependent Hamiltonian. As an application of this method, we propose a THz probe technique to obtain spatially resolved information about the electronic spectra inside gated nanowires. This spectroscopic approach employs a segmented multigate design for the local detection of quantum transitions between few-electron states. The obtained simulation results for the intraband THz response spectrum show fingerprints for the formation of Wigner molecules inside the nanowire in the long channel limit.

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“…Recently, we have presented a multiconfigurational selfconsistent Green's function ͑MCSCGF͒ approach, 9 which represents a consistent extension of the mean-field NEGF method for the inclusion of single-electron effects under application-relevant conditions. This approach combines the simplicity and scalability of the mean-field NEGF approach with a many-body Fock space description of the Coulomb interaction of those electrons that are resonantly trapped within the nanostructure.…”

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confidence: 99%

Quantum confinement corrections to the capacitance of gated one-dimensional nanostructures

Indlekofer

Knoch

Appenzeller³

2006

Phys. Rev. B

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With the help of a multiconfigurational Green's function approach we simulate single-electron Coulomb charging effects in gated ultimately scaled nanostructures which are beyond the scope of a self-consistent mean-field description. From the simulated Coulomb-blockade characteristics we derive effective system capacitances and demonstrate how quantum confinement effects give rise to corrections. Such deviations are crucial for the interpretation of experimentally determined capacitances and the extraction of applicationrelevant system parameters. DOI: 10.1103/PhysRevB.74.113310 PACS number͑s͒: 73.63.Ϫb, 72.10.Ϫd, 73.22.Ϫf, 73.23.Ϫb One of the major challenges for the simulation of electronic transport in low-dimensional nanostructures consists in an adequate description of the Coulomb interaction. In ultimately scaled semiconductor nanosystems, only a few electrons constitute the current. Thus, the details of the electron-electron interaction may become crucial for the electronic properties, as can be seen in experimentally observed single-electron charging effects in carbon nanotubes and III-V nanowhiskers.1,2 The channel region of a typical application-relevant nanostructure involves on the order of 100 single-particle states ͑or sites͒ and can be highly inhomogeneous and anisotropic. Here, external contacts and gate electrodes in general introduce nonlinear perturbations to the system. Hence, highly idealized interacting few-level models with a small number of effective parameters ͑constants͒ become inadequate. For a realistic simulation of quantum transport in application-relevant nanodevices, various approaches have been used, differing in the formulation of Coulomb interaction and contact coupling. While the orthodox theory 3,4 correctly describes few-electron effects such as single-electron tunneling in quasi-isolated quantum dot systems, the nonequilibrium Green's function ͑NEGF͒ formalism 5-8 also accounts for contact renormalization and dissipation terms. However, the NEGF formalism becomes unable to describe the details of charging effects of a few fluctuating electrons as soon as a mean-field approximation is introduced.Recently, we have presented a multiconfigurational selfconsistent Green's function ͑MCSCGF͒ approach, 9 which represents a consistent extension of the mean-field NEGF method for the inclusion of single-electron effects under application-relevant conditions. This approach combines the simplicity and scalability of the mean-field NEGF approach with a many-body Fock space description of the Coulomb interaction of those electrons that are resonantly trapped within the nanostructure. As a key element, the algorithm identifies "relevant" trapped single-particle states that are subject to occupation fluctuations. Within the resulting relevant Fock subspace, many-body "configurations" and associated weights w are defined as eigenstates and eigenvalues of the projected many-body statistical operator MB , respectively. Consequently, the system Green's functions are written as weighted avera...

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Quantum kinetic description of Coulomb effects in one-dimensional nanoscale transistors

Cited by 26 publications

References 32 publications

Remarks on theoretical modelling of spin-dependent electronic transport in carbon nanotubes and graphene

Remarks on theoretical modelling of spin-dependent electronic transport in carbon nanotubes and graphene

Many-body approach to the terahertz response of Wigner molecules in gated nanowire structures

Quantum confinement corrections to the capacitance of gated one-dimensional nanostructures

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