Correlation-Induced Conductance Suppression at Level Degeneracy in a Quantum Dot

Nilsson, Henrik; Karlström, Olov; Larsson, Marcus; Caroff, Philippe; Pedersen, Jonas Nyvold; Samuelson, Lars; Wacker, Andreas; Wernersson, Lars‐Erik; Xu, Hongqi

doi:10.1103/physrevlett.104.186804

Cited by 59 publications

(95 citation statements)

References 23 publications

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“…Furthermore, it was shown in Ref. 18 that good agreement between theory and experiment could be achieved for real couplings. As the broadening of the levels is proportional to the square of the coupling elements we have…”

Section: Introductionmentioning

confidence: 99%

“…18 can be found only in a certain parameter space or if it is generic for the studied two-level system. We plot the normalized current J /V bias , which equals the conductance G in the low-bias limit.…”

Section: The Canyon Of Conductance Suppressionmentioning

confidence: 99%

“…On the experimental side, the degeneracy of orbital levels was recently studied for a gate-defined quantum dot in an InSb nanowire, 18 where a canyon of conductance suppression was found. Here large level-dependent g-factors enabled the study of degenerate orbital levels using the Zeeman effect.…”

Section: Introductionmentioning

confidence: 99%

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Canyon of current suppression in an interacting two-level quantum dot

Karlström¹,

Pedersen²,

Samuelsson³

et al. 2011

Phys. Rev. B

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Motivated by the recent discovery of a canyon of conductance suppression in a two-level equal spin quantum dot system [Phys. Rev. Lett. 104, 186804 (2010)] the transport through this system is studied in detail. At low bias and low temperature a strong current suppression is found around the electron-hole symmetry point independent of the couplings, in agreement with previous results. By means of a Schrieffer-Wolff transformation we are able to give an intuitive explanation to this suppression in the low-energy regime. In the general situation, numerical simulations are carried out using quantum rate equations. The simulations allow for the prediction of how the suppression is affected by the couplings, the charging energy, the position of the energy levels, the applied bias, and the temperature. We find that away from electron-hole symmetry, the parity of the couplings is essential for the current suppression. It is also shown how broadening, interference, and a finite interaction energy cause a shift of the current minimum away from degeneracy. Finally we see how an increased population of the upper level leads to current peaks on each side of the suppression line. At sufficiently high bias we discover a coherence-induced population inversion.

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Section: Introductionmentioning

confidence: 99%

Section: The Canyon Of Conductance Suppressionmentioning

confidence: 99%

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Canyon of current suppression in an interacting two-level quantum dot

Karlström¹,

Pedersen²,

Samuelsson³

et al. 2011

Phys. Rev. B

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“…The flow of electrons through a quantum dot between reservoirs is a versatile tool for addressing a wide range of fundamental effects, ranging from the structure of electronic many-particle states [1,2] and Kondo physics [3][4][5], to quantifying the spin dephasing due to coupling to nuclear degrees of freedom [6][7][8] or coherent effects [9].…”

Section: General Rightsmentioning

confidence: 99%

Total Current Blockade in an Ultracold Dipolar Quantum Wire

et al. 2013

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Total current blockade in an ultracold dipolar quantum wire.Kristinsdottir, Liney Halla; Karlström, Olov; Bjerlin, Johannes; Cremon, Jonas; Schlagheck, P; Wacker, Andreas; Reimann, Stephanie General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal Take down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Cold-atom systems offer a great potential for the future design of new mesoscopic quantum systems with properties that are fundamentally different from semiconductor nanostructures. Here, we investigate the quantum-gas analogue of a quantum wire and find a new scenario for the quantum transport: Attractive interactions may lead to a complete suppression of current in the low-bias range, a total current blockade. We demonstrate this effect for the example of ultracold quantum gases with dipolar interactions.

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“…We consider here approximate master equation approaches, which were also used to interpret transport experimental data in the regime of weak coupling to the environment [23,24,25]. In particular, we address the so-called Pauli master equation [6,26,27], the first-order Redfield approach [6,28,29], the first/second-order von Neumann approaches [19,30], and a particular form of the Lindblad equation [31,32], and apply these methods for tunneling models, where the quantum dots can have arbitrary Coulomb interactions [33].…”

Section: Introductionmentioning

confidence: 99%

QmeQ 1.0: An open-source Python package for calculations of transport through quantum dot devices

Wacker

Pedersen

Karlström

et al. 2017

Computer Physics Communications

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QmeQ is an open-source Python package for numerical modeling of transport through quantum dot devices with strong electron-electron interactions using various approximate master equation approaches. The package provides a framework for calculating stationary particle or energy currents driven by differences in chemical potentials or temperatures between the leads which are tunnel coupled to the quantum dots. The electronic structures of the quantum dots are described by their single-particle states and the Coulomb matrix elements between the states. When transport is treated perturbatively to lowest order in the tunneling couplings, the possible approaches are Pauli (classical), firstorder Redfield, and first-order von Neumann master equations, and a particular form of the Lindblad equation. When all processes involving two-particle excitations in the leads are of interest, the second-order von Neumann approach can be applied. All these approaches are implemented in QmeQ. We here give an overview of the basic structure of the package, give examples of transport calculations, and outline the range of applicability of the different approximate approaches. Keywords: Open quantum systems, Quantum dots, Anderson-type model, Coulomb blockade, Python Program summaryProgram Title: QmeQ Licensing provisions: BSD 2-Clause Programming language: Python External libraries: NumPy, SciPy, Cython Nature of problem: Calculation of stationary state currents through quantum dots tunnel coupled to leads. Solution method: Exact diagonalisation of the quantum dot Hamiltonian for a given set of single particle states and Coulomb matrix elements. Numerical solution of the stationary-state master equation for a given approximate approach. Restrictions: Depending on the approximate approach the temperature needs to be sufficiently large compared to the coupling strength for the approach to be valid.

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Correlation-Induced Conductance Suppression at Level Degeneracy in a Quantum Dot

Cited by 59 publications

References 23 publications

Canyon of current suppression in an interacting two-level quantum dot

Canyon of current suppression in an interacting two-level quantum dot

Total Current Blockade in an Ultracold Dipolar Quantum Wire

QmeQ 1.0: An open-source Python package for calculations of transport through quantum dot devices

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