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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 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…

Intrinsic and extrinsic valley Hall effects are predicted to emerge in graphene systems with uniform or spatially-varying mass terms. Extrinsic mechanisms, mediated by the valley-dependent scattering of electrons at the Fermi surface, can…

Mesoscale and Nanoscale Physics · Physics 2021-07-07 Fionnuala Solomon , Stephen R. Power

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

Manipulating the valley degree of freedom to encode information for potential valleytronic devices has ignited a new direction in solid-state physics. A significant, fundamental challenge in the field of valleytronics is how to generate and…

Mesoscale and Nanoscale Physics · Physics 2020-07-02 Hui-Ying Mu , Yi-Tong Yao , Jie-Ru Li , Guo-Cai Liu , Chao He , Ying-Jie Sun , Guang Yang , Xing-Tao An , Yong-Zhe Zhang , Jian-Jun Liu

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

Valley polarization in graphene breaks inversion symmetry and therefore leads to second-harmonic generation. We present a complete theory of this effect within a single-particle approximation. It is shown that this may be a sensitive tool…

Mesoscale and Nanoscale Physics · Physics 2015-06-22 T. O. Wehling , A. Huber , A. I. Lichtenstein , M. I. Katsnelson

We study transport in twisted bilayer graphene and show that electrostatic barriers can act as valley splitters, where electrons from the $K$ ($K'$) valley are transmitted only to e.g.\ the top (bottom) layer, leading to valley-layer locked…

Mesoscale and Nanoscale Physics · Physics 2020-10-30 Christophe De Beule , Peter G. Silvestrov , Ming-Hao Liu , Patrik Recher

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

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

The extremely high pseudo-magnetic field emerging in strained graphene suggests that an oscillating nano-deformation will induce a very high current even without electric bias. In this paper, we demonstrate the sub-terahertz (THz) dynamics…

Mesoscale and Nanoscale Physics · Physics 2025-10-24 Naif Hadadi , Adel Belayadi , Ahmed AlRabiah , Ousmane Ly , Collins Ashu Akosa , Michael Vogl , Hocine Bahlouli , Aurelien Manchon , Adel Abbout

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

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

This work investigates the feasibility of electrical valley filtering for holes in transition metal dichalcogenides. We look specifically into the scheme that utilizes a potential barrier to produce valley-dependent tunneling rates, and…

Mesoscale and Nanoscale Physics · Physics 2020-05-12 Tzu-Chi Hsieh , Mei-Yin Chou , Yu-Shu Wu

We propose three-terminal spin devices with graphene nanoribbons (terminals) and a graphene flake (channel) to generate a highly spin-polarized current without an external magnetic field or ferromagnetic electrodes. The Hubbard repulsion…

Mesoscale and Nanoscale Physics · Physics 2015-10-20 Rouhollah Farghadan , Alireza Saffarzadeh

Spatially varying strained graphene can acquire interesting electronic properties because of the strain-induced valley-dependent gauge (pseudomagnetic) fields1,2. Here we report the realization of strained graphene regions located close to…

Materials Science · Physics 2015-03-31 Jun-Fang Liu , Ke-Ke Bai , Jia-Bin Qiao , Yu Zhou , Jia-Cai Nie , Hailin Peng , Zhongfan Liu , Lin He

The possibility to effect valley splitting of an electronic current in graphene represents the essential component in the new field of valleytronics in such two-dimensional materials. Based on a symmetry analysis of the scattering matrix,…

Mesoscale and Nanoscale Physics · Physics 2017-11-22 Mahmoud M. Asmar , Sergio E. Ulloa

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…

We study the effect of the strain on the band structure and the valley-dependent transport property of graphene heterojunctions. It is found that valley-dependent separation of electrons can be achieved by utilizing the strain and on-site…

Mesoscale and Nanoscale Physics · Physics 2022-06-17 Fei Wan , Xinru Wang , Liehong Liao , Jiayan Zhang , M. N. Chen , G. H. Zhou , Z. B. Siu , Mansoor B. A. Jalil , Yuan Li

Particular strain geometry in graphene could leads to a uniform pseudo-magnetic field of order 10T and might open up interesting applications in graphene nano-electronics. Through quantum transport calculations of realistic strained…

Mesoscale and Nanoscale Physics · Physics 2015-03-13 Tony Low , F. Guinea