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Analogous to charge and spin, electrons in solids endows an additional degree of freedom: the valley pseudospin. Two-dimensional hexagonal materials such as graphene exhibit two valleys, labelled as $\mathbf{K}$ and $\mathbf{K}^{\prime}$.…

Mesoscale and Nanoscale Physics · Physics 2022-01-12 M. S. Mrudul , Gopal Dixit

We study ballistic transport of Dirac electrons through a strip in silicene, when the strip is exposed to off-resonant circularly polarized light and an electric field applied perpendicular to the silicene plane. We show that the…

Mesoscale and Nanoscale Physics · Physics 2016-06-22 Yawar Mohammadi , Borhan Arghavani Nia

We recently shown, using tight-binding calculations, that nonequilibrium valley polarization can be realized in graphene, when the current is injected through "valley filter": a ballistic point contact with zigzag edges. Here we…

Mesoscale and Nanoscale Physics · Physics 2008-05-23 Adam Rycerz

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

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 theoretically investigate the effects of strain-induced pseudomagnetic fields on the transmission probability and the ballistic conductance for Dirac fermion transport in suspended graphene. We show that resonant tunneling through double…

Mesoscale and Nanoscale Physics · Physics 2014-02-19 Nojoon Myoung , Gukhyung Ihm

Valleytronics using two-dimensional materials opens unprecedented opportunities for information processing with the valley polarizer being a basic building block. Paradigms such as strain engineering, the inclusion of line defects, and the…

Mesoscale and Nanoscale Physics · Physics 2023-06-07 Shrushti Tapar , Bhaskaran Muralidharan

We consider tunneling transport between two parallel graphene sheets where one is a single-layer sample and the other one a bilayer. In the presence of an in-plane magnetic field, the interplay between combined energy and momentum…

Mesoscale and Nanoscale Physics · Physics 2014-02-25 L Pratley , U. Zuelicke

Propagation of an electron wave packet through a quantum point contact (QPC) defined by electrostatic gates in bilayer graphene is investigated. The gates provide a bias between the layers, in order to produce an energy gap. If the gates on…

Mesoscale and Nanoscale Physics · Physics 2016-01-05 D. R. da Costa , A. Chaves , S. H. R. Sena , G. A. Farias , F. M. Peeters

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

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

Electrons in graphene, in addition to their spin, have two pseudospin degrees of freedom: sublattice and valley pseudospin. Valleytronics uses the valley degree of freedom as a carrier of information similar to the way spintronics uses…

Mesoscale and Nanoscale Physics · Physics 2013-04-03 D. Moldovan , M. Ramezani Masir , L. Covaci , F. M. Peeters

We present a single barrier system to generate pure valley-polarized current in monolayer graphene. A uniaxial strain is applied within the barrier region, which is delineated by localized magnetic field created by ferromagnetic stripes at…

Mesoscale and Nanoscale Physics · Physics 2016-03-07 Can Yesilyurt , Seng Ghee Tan , Gengchiau Liang , Mansoor B. A. Jalil

Probing and controlling the valley degree of freedom in graphene systems by transport measurements has been a major challenge to fully exploit the unique properties of this two-dimensional material. In this theoretical work, we show that…

Mesoscale and Nanoscale Physics · Physics 2022-11-09 Feng-Wu Chen , Nin-Yuan Lue , Mei-Yin Chou , Yu-Shu G. Wu

The low energy band structure of graphene has two inequivalent valleys at K and K' points of the Brillouin zone. The possibility to manipulate this valley degree of freedom defines the field of valleytronics, the valley analogue of…

Mesoscale and Nanoscale Physics · Physics 2017-01-11 Mikkel Settnes , Stephen R. Power , Mads Brandbyge , Antti-Pekka Jauho

The Corbino geometry allows one to investigate the propagation of electric current along a p-n interface in ballistic graphene in the absence of edge states appearing for the familiar Hall-bar geometry. Using the transfer matrix in the…

Mesoscale and Nanoscale Physics · Physics 2020-02-21 Dominik Suszalski , Grzegorz Rut , Adam Rycerz

The generation of a fully valley-polarized current (FVPC) in bulk graphene is a fundamental goal in valleytronics. To this end, we investigate valley-dependent transport through a strained graphene modulated by a finite magnetic…

Mesoscale and Nanoscale Physics · Physics 2013-11-04 Yu Song , Feng Zhai , Yong Guo

The paper presents a theoretical description of the effects of strain induced by out-of-plane deformations on charge distributions and transport on graphene. A review of a continuum model for electrons using the Dirac formalism is…

Mesoscale and Nanoscale Physics · Physics 2019-10-15 Dawei Zhai , Nancy Sandler

This work performs a numerical study of electron transport through the fundamental logic gate in valleytronics - a valley valve consisting of two or increasing number of valley filters. Various typical effects on the transport are…

Mesoscale and Nanoscale Physics · Physics 2022-11-09 Jia-Huei Jiang , Ning-Yuan Lue , Feng-Wu Chen , Yu-Shu G. Wu

A valley filter capable of generating a valley-polarized current is a crucial element in valleytronics, yet its implementation remains challenging. Here, we propose a valley filter made of a graphene bilayer which exhibits a 1D moir\'{e}…

Mesoscale and Nanoscale Physics · Physics 2024-04-19 Kai Shao , Hao Geng , Erfu Liu , Jose L. Lado , Wei Chen , D. Y. Xing