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In this work we investigate theoretically the influence of a Fermi velocity modulation in the electronic and transport properties of magnetic graphene superlattices. We solve the effective Dirac equation for graphene with a position…

Mesoscale and Nanoscale Physics · Physics 2020-05-21 Ícaro S. F. Bezerra , Jonas R. F. Lima

In this Letter, both the manipulation of valley-polarized currents and the optical-like behaviors of Dirac fermions are theoretically explored in polycrystalline graphene. When strain is applied, the misorientation between two graphene…

Mesoscale and Nanoscale Physics · Physics 2016-12-14 Viet Hung Nguyen , Samuel Dechamps , Philippe Dollfus , Jean-Christophe Charlier

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

Valley filters are crucial to any device exploiting the valley degree of freedom. By using an atomistic model, we analyze the mechanism leading to the valley filtering produced by a line-defect in graphene and show how it can be inverted by…

Mesoscale and Nanoscale Physics · Physics 2016-10-11 Lucas H. Ingaramo , Luis E. F. Foa Torres

In addition to electron charge and spin, novel materials host another degree of freedom, the valley. For a junction composed of valley filter sandwiched by two normal terminals, we focus on the valley efficiency under disorder with two…

Mesoscale and Nanoscale Physics · Physics 2017-11-29 Shu-guang Cheng , Jiaojiao Zhou , Hua Jiang , Qing-Feng Sun

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

Due to their possibility to encode information and realize low-energy-consumption quantum devices, control and manipulation of the valley degree of freedom have been widely studied in electronic systems. In contrast, the phononic…

Mesoscale and Nanoscale Physics · Physics 2019-02-25 Xiaobin Chen , Yong Xu , Jian Wang , Hong Guo

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

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 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

Using full-potential density functional theory (DFT) calculations, we found a small asymmetry in the Fermi velocity of electrons and holes in graphene. These Fermi velocity values and their average were found to decrease with increasing…

Mesoscale and Nanoscale Physics · Physics 2013-02-08 Harihar Behera , Gautam Mukhopadhyay

The Fermi velocity is one of the key concepts in the study of a material, as it bears information on a variety of fundamental properties. Upon increasing demand on the device applications, graphene is viewed as a prototypical system for…

Mesoscale and Nanoscale Physics · Physics 2012-08-21 Choongyu Hwang , David A. Siegel , Sung-Kwan Mo , William Regan , Ariel Ismach , Yuegang Zhang , Alex Zettl , Alessandra Lanzara

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 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

In this work we investigate the influence of a Fermi velocity modulation on the Fano factor of periodic and quasi-periodic graphene superlattices. We consider the continuum model and use the transfer matrix method to solve the Dirac-like…

Mesoscale and Nanoscale Physics · Physics 2017-11-22 Jonas R. F. Lima , Anderson L. R. Barbosa , C. G. Bezerra , Luiz Felipe C. Pereira

The electronic structure of a single-layer graphene with a periodic Fermi velocity modulation is investigated by using an effective Dirac-like Hamiltonian. In a gapless graphene or in a graphene with a constant energy gap the modulation of…

Materials Science · Physics 2014-12-02 Jonas R. F. Lima

The conduction properties of a grain boundary junction with Fermi velocity mismatch are analyzed. We provide a generalization of the Dirac Hamiltonian model taking into account the Fermi velocity gradient at the interface. General boundary…

Mesoscale and Nanoscale Physics · Physics 2021-01-29 Francesco Romeo

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

Here we theoretically investigate the valley-dependent transmission of particles through a combined electric and magnetic barrier in the $\alpha-T_3$ model which interpolates between the honeycomb and the dice lattices. We put forward that…

Mesoscale and Nanoscale Physics · Physics 2020-09-02 F. Bouhadida , L. Mandhour , S. Charfi-Kaddour

We propose an all-electrical setup to generate valley polarization in graphene. A finite graphene sheet is connected to two normal metal electrodes each with two terminals along its zigzag edges, while the armchair edges remain free. When a…

Mesoscale and Nanoscale Physics · Physics 2025-06-30 Sachchidanand Das , Abhiram Soori
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