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Valley-polarized currents can be generated by local straining of multi-terminal graphene devices. The pseudo-magnetic field created by the deformation allows electrons from only one valley to transmit and a current of electrons from a…

Mesoscale and Nanoscale Physics · Physics 2016-11-18 S. P. Milovanovic , F. M. Peeters

We show that a system of Josephson junctions coupled via low-resistance tunneling contacts to graphene substrate(s) may effectively operate as a current switching device. The effect is based on the dissipation-driven…

Superconductivity · Physics 2009-11-13 Roman M. Lutchyn , Victor Galitski , Gil Refael , S. Das Sarma

We compute the current and the noise power matrix in a quantum dot connected to two metallic reservoirs by using the Keldysh field theory approach, a non-equilibrium quantum field theory language in the functional integral formalism. We…

Mesoscale and Nanoscale Physics · Physics 2024-11-20 Marco Uguccioni , Luca Dell'Anna

We theoretically study valley-filtering in pristine graphene irradiated by bicircular counter-rotating laser drive. The dynamical symmetry of the graphene and laser drive disrupts graphene's inversion symmetry, which results distinct…

Mesoscale and Nanoscale Physics · Physics 2024-01-23 Rekha Kumari , Gopal Dixit , Arijit Kundu

We report a theoretical analysis of parametric electron pump through a quantum dot in the Kondo regime. In the adiabatic regime, we have derived the expression for pumped current in the Kondo regime using non-equilibrium Green's function.…

Condensed Matter · Physics 2009-11-07 Baigeng Wang , Jian Wang

Using the Bardeen tunneling method with first-principles wave functions, computations are made of the tunneling current in graphene / hexagonal-boron-nitride / graphene (G/h-BN/G) vertical structures. Detailed comparison with prior…

Mesoscale and Nanoscale Physics · Physics 2018-07-19 Randall M. Feenstra , Sergio C. de la Barrera , Jun Li , Yifan Nie , Kyeongjae Cho

Quantum pumping processes are accompanied by considerable quantum noise. We investigated the pumped shot noise (PSN) properties in adiabatically modulated graphene-based double-barrier structures. General expressions for adiabatically PSN…

Mesoscale and Nanoscale Physics · Physics 2015-05-28 Rui Zhu , Maoli Lai

We show that gapped Graphene, with a local constraint that current arising from the two valley fermions are exactly equal, shows a non-BCS type superconductivity. Unlike the conventional mechanisms, this superconductivity phenomenon does…

Superconductivity · Physics 2011-07-28 Vivek M. Vyas , Prasanta K. Panigrahi

The theoretical results are presented showing that strain-induced anisotropy of graphene spectrum gives rise to the valley currents under the illumination by normally incident light. The currents of the two graphene valleys are mutually…

Mesoscale and Nanoscale Physics · Physics 2014-08-13 T. L. Linnik

An analogue of the Datta-Das spin FET is investigated, which is all-graphene and based on the valley degree of freedom of electrons / holes. The "valley FET" envisioned consists of a quantum wire of gapped graphene (channel) sandwiched…

Mesoscale and Nanoscale Physics · Physics 2013-01-01 M. -K. Lee , N. -Y. Lue , Y. -C. Chen , C. -K. Wen , G. Y. Wu

Quantum charge pumping, the quantum coherent generation of a dc current at zero bias through time dependent potentials, provides outstanding opportunities for metrology and the development of new devices. The long electronic coherence times…

Mesoscale and Nanoscale Physics · Physics 2013-09-27 Lucas H. Ingaramo , Luis E. F. Foa Torres

We investigate the behavior of the directed current in one-dimensional systems of Dirac fermions driven by local periodic potentials in the forward as well in backscattering channels. We treat the problem with Keldysh non-equilibrium…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 L. Arrachea , Carlos Naón , Mariano Salvay

We propose a simple, yet highly efficient and robust device for producing valley polarized current in graphene. The device comprises of two distinct components; a region of uniform uniaxial strain, adjacent to an out-of-plane magnetic…

Mesoscale and Nanoscale Physics · Physics 2010-08-06 T. Fujita , M. B. A. Jalil , S. G. Tan

A Zener diode is a paradigmatic device in semiconductor-based electronics that consists of a pn junction where an external electric field induces a switching behavior in the current-voltage characteristics. We study Zener tunneling in HgTe…

Mesoscale and Nanoscale Physics · Physics 2012-06-29 Martha Lasia , Elsa Prada , Luis Brey

We review the construction of a low-energy effective field theory and its state space for "abelian" quantum Hall fluids. The scaling limit of the incompressible fluid is described by a Chern-Simons theory in 2+1 dimensions on a manifold…

Mesoscale and Nanoscale Physics · Physics 2012-03-05 Samuel Bieri , Juerg Froehlich

We demonstrate that the influence of Kerr effect on valley-Hall topological transport in graphene metasurfaces can be used to implement an all-optical switch. In particular, by taking advantage of the large Kerr coefficient of graphene, the…

Optics · Physics 2023-03-09 Yupei Wang , Jian Wei You , Nicolae C. Panoiu

We describe the numerical modeling of current flow in graphene heterojunctions, within the Keldysh Landauer Non-equilibrium Green's function (NEGF) formalism. By implementing a $k$-space approach along the transverse modes, coupled with…

Mesoscale and Nanoscale Physics · Physics 2013-07-02 Redwan N. Sajjad , Carlos Polanco , Avik W. Ghosh

We have utilized the finite-difference approach to explore electron-tunneling properties in gapped graphene through various electrostatic-potential barriers changing from Gaussian to a triangular envelope function in comparison with a…

Mesoscale and Nanoscale Physics · Physics 2021-10-27 Farhana Anwar , Andrii Iurov , Danhong Huang , Godfrey Gumbs , Ashwani Sharma

We develop a quantum field theory for parametrically pumped polaritons using Keldysh Green's function techniques. By considering the mean-field and Gaussian fluctuations, we find that the low energy physics of the highly non-equilibrium…

Quantum Gases · Physics 2016-10-28 K. Dunnett , M. H. Szymańska

Elastic deformations of graphene can significantly change the flow paths and valley polarization of the electric currents. We investigate these phenomena in graphene nanoribbons with localized out-of-plane deformations by means of…

Mesoscale and Nanoscale Physics · Physics 2019-03-12 Thomas Stegmann , Nikodem Szpak