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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

Graphene, and other members of the monolayer Xene family, represent an ideal materials platform for "valleytronics", the control of valley localized charge excitations. The absence of a gap in these semi-metals, however, precludes valley…

We show how the trigonal warping effect in doped graphene can be used to produce fully valley polarized currents. We propose a device that acts both as a beam splitter and a collimator of these electronic currents. The result is…

Mesoscale and Nanoscale Physics · Physics 2007-10-05 J. L. Garcia-Pomar , A. Cortijo , M. Nieto-Vesperinas

With its two degenerate valleys at the Fermi level, the band structure of graphene provides the opportunity to develop unconventional electronic applications. Herein, we show that electron and hole quasiparticles in graphene can be filtered…

Mesoscale and Nanoscale Physics · Physics 2011-04-29 Daniel Gunlycke , Carter T. White

Electrons in two-dimensional hexagonal materials have valley degree of freedom, which can be used to encode and process quantum information. The valley-selective excitations, governed by the circularly polarised light resonant with the…

Mesoscale and Nanoscale Physics · Physics 2021-03-19 M. S. Mrudul , Álvaro Jiménez-Galán , Misha Ivanov , Gopal Dixit

It is quite easy to control spin polarization and spin direction of a system via magnetic fields. However, there is no such a direct and efficient way to manipulate valley pseudospin degree of freedom. Here, we demonstrate experimentally…

Mesoscale and Nanoscale Physics · Physics 2020-03-18 Si-Yu Li , Ying Su , Ya-Ning Ren , Lin He

We study theoretically the electron current across a monolayer graphene/hexagonal boron nitride/bilayer graphene tunnelling junction in an external magnetic field perpendicular to the layers. We show that change in effective tunnelling…

Mesoscale and Nanoscale Physics · Physics 2019-02-18 J. J . P. Thompson , D. J. Leech , M. Mucha-Kruczyński

We study theoretically interaction of a bilayer graphene with a circularly polarized ultrafast optical pulse of a single oscillation at an oblique incidence. The normal component of the pulse breaks the inversion symmetry of the system and…

Mesoscale and Nanoscale Physics · Physics 2021-11-10 Pardeep Kumar , Thakshila M. Herath , Vadym Apalkov

Realizations of some topological phases in two-dimensional systems rely on the challenge of jointly incorporating spin-orbit and magnetic exchange interactions. Here, we predict the formation and control of a fully valley-polarized quantum…

Mesoscale and Nanoscale Physics · Physics 2021-10-25 Marc Vila , Jose H. Garcia , Stephan Roche

We propose a device in which a sheet of graphene is coupled to a Weyl semimetal, allowing for the physical access to the study of tunneling from two-dimensional to three dimensional massless Dirac fermions. Due to the reconstructed band…

Mesoscale and Nanoscale Physics · Physics 2021-09-17 Ahmed Khalifa , Ribhu K. Kaul , Efrat Shimshoni , Herbert A. Fertig , Ganpathy Murthy

Quantum transport calculations describing electron scattering off an extended line defect in graphene are presented. The calculations include potentials from local magnetic moments recently predicted to exist on sites adjacent to the line…

Mesoscale and Nanoscale Physics · Physics 2012-05-18 Daniel Gunlycke , Carter T. White

We discuss valley current, which is carried by quasiparticles in graphene. We show that the valley current arises owing to a peculiar term in the electron-phonon collision integral that mixes the scalar and vector gauge-field-like vertices…

Mesoscale and Nanoscale Physics · Physics 2023-05-10 Ankang Liu , Alexander M. Finkel'stein

Because the valleys in the band structure of graphene are related by time-reversal symmetry, electrons from one valley are reflected as holes from the other valley at the junction with a superconductor. We show how this Andreev reflection…

Mesoscale and Nanoscale Physics · Physics 2013-07-09 A. R. Akhmerov , C. W. J. Beenakker

The achievement of valley-polarized electron currents is a cornerstone for the realization of valleytronic devices. Here, we report on ballistic coherent transport experiments where two opposite quantum point contacts (QPCs) are defined by…

The valley degree of freedom in 2D materials can be manipulated for low-dissipation quantum electronics called valleytronics. At the boundary between two regions of bilayer graphene with different atomic or electrostatic configuration,…

Mesoscale and Nanoscale Physics · Physics 2024-04-03 Konstantin Davydov , Xi Zhang , Wei Ren , Matthew Coles , Logan Kline , Bryan Zucker , Kenji Watanabe , Takashi Taniguchi , Ke Wang

Control over minivalley polarization and interlayer coupling is demonstrated in double bilayer graphene twisted with an angle of 2.37$^\circ$. This intermediate angle is small enough for the minibands to form and large enough such that the…

Valley filtering processes have been explored in different graphene-based configurations and scenarios to control transport responses. Here we propose graphene multi-terminal set-ups properly designed to obtain valley filtered currents in a…

Mesoscale and Nanoscale Physics · Physics 2021-03-31 Vanessa Torres , Daiara Faria , Andrea Latgé

We investigate the electronic dispersion and transport properties of graphene/WSe$_{2}$ heterostructures in the presence of a proximity-induced spin-orbit coupling $\lambda_{v}$, sublattice potential $\Delta$, and an off-resonant circularly…

Mesoscale and Nanoscale Physics · Physics 2023-07-07 M. Zubair , P. Vasilopoulos , M. Tahir

Due to its strong bonds graphene can stretch up to 25% of its original size without breaking. Furthermore, mechanical deformations lead to the generation of pseudo-magnetic fields (PMF) that can exceed 300 T. The generated PMF has opposite…

Mesoscale and Nanoscale Physics · Physics 2017-11-22 Slavisa P. Milovanovic , Francois M. Peeters

Considering the difference of energy bands in graphene and silicene, we put forward a new model of the graphene-silicene-graphene (GSG) heterojunction. In the GSG, we study the valley polarization properties in a zigzag nanoribbon in the…

Mesoscale and Nanoscale Physics · Physics 2015-06-18 Man Shen , Yan-Yang Zhang , Xing-Tao An , Jian-Jun Liu , Shu-Shen Li