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Recent experiments have revealed that novel nonequilibrium states consistent with the hydrodynamic description of electrons are realized in ultrapure graphene, which hosts the valley degrees of freedom. Here, we formulate a theory of…

Mesoscale and Nanoscale Physics · Physics 2022-05-05 Ryotaro Sano , Daigo Oue , Mamoru Matsuo

Band gap engineering in graphene may open the routes towards transistor devices in which electric current can be switched off and on at will. One may, however, ask if a semiconducting band gap alone is sufficient to quench the current in…

Mesoscale and Nanoscale Physics · Physics 2012-11-12 G. Tkachov , Martina Hentschel

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

We study electron transport properties of a monoatomic graphite layer (graphene) with different types of disorder at half filling. We show that the transport properties of the system depend strongly on the symmetry of disorder. We find that…

Mesoscale and Nanoscale Physics · Physics 2007-10-04 P. M. Ostrovsky , I. V. Gornyi , A. D. Mirlin

In strained graphene, lattice deformation can create pseudo-magnetic fields and result in zero-field Landau level-like quantization. In the presence of an external magnetic field, valley-polarized Landau levels are predicted to be observed…

Mesoscale and Nanoscale Physics · Physics 2015-12-16 Si-Yu Li , Ke-Ke Bai , Long-Jing Yin , Jia-Bin Qiao , Wen-Xiao Wang , Lin He

We study the electron scattering produced by local out-of-plane strain deformations in the form of Gaussian bumps in graphene. Of special interest is to take into account the scalar field associated with the redistribution of charge due to…

Mesoscale and Nanoscale Physics · Physics 2018-10-30 Ramon Carrillo-Bastos , Marysol Ochoa , Saúl A. Zavala , Francisco Mireles

We investigated the electronic structure, Fermi surface topology and the emergence of valley imbalance in rhombohedral trilayer graphene (RTG) induced by the topological proximity and the electric fields. We show that, a strong proximity…

Mesoscale and Nanoscale Physics · Physics 2025-10-30 Sovan Ghosh , Bheema Lingam Chittari

Ballistic point contact (BPC) with zigzag edges in graphene is a main candidate of a valley filter, in which the polarization of the valley degree of freedom can be selected by using a local gate voltage. Here, we propose to detect the…

Mesoscale and Nanoscale Physics · Physics 2017-12-27 Kun Luo , Tao Zhou , Wei Chen

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

Atomically precise tailoring of graphene can enable unusual transport pathways and new nanometer-scale functional devices. Here we describe a recipe for the controlled production of highly regular "5-5-8" line defects in graphene by means…

Mesoscale and Nanoscale Physics · Physics 2014-06-05 J. -H. Chen , G. Autès , N. Alem , F. Gargiulo , A. Gautam , M. Linck , C. Kisielowski , O. V. Yazyev , S. G. Louie , A. Zettl

The paper addresses boundary electronic properties of graphene with a complex edge structure of the armchair/zigzag/armchair type. It is shown that the finite zigzag region supports edge bound states with discrete equidistant spectrum…

Mesoscale and Nanoscale Physics · Physics 2009-02-02 Grigory Tkachov

We report on the possibility to simultaneously generate in graphene a {\it bulk valley-polarized dissipative transport} and a {\it quantum valley Hall effect} by combining strain-induced gauge fields and real magnetic fields. Such unique…

Mesoscale and Nanoscale Physics · Physics 2018-08-01 Mikkel Settnes , José Hugo García , Stephan Roche

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 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

When graphene is deformed in a dynamical manner, a time-dependent potential is induced for the electrons. The potential is antisymmetric with respect to valleys, and some straightforward applications are found for Raman spectroscopy. We…

Mesoscale and Nanoscale Physics · Physics 2014-11-17 Ken-ichi Sasaki , Yasuhiro Tokura , Hideki Gotoh

Ferroelectricity (Valasek, J. Phys. Rev. 1921, 17, 475) - a spontaneous formation of electric polarisation - is a solid state phenomenon, usually, associated with ionic compounds or complex materials. Here we show that, atypically for…

Materials Science · Physics 2023-05-29 Aitor Garcia-Ruiz , Vladimir Enaldiev , Andrew McEllistrim , Vladimir I. Fal'ko

We calculate the conductance G of a bipolar junction in a graphene nanoribbon, in the high-magnetic field regime where the Hall conductance in the p-doped and n-doped regions is 2e^2/h. In the absence of intervalley scattering, the result…

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

We address the intrinsic polarisation and screening of external electric field in a broad range of ordered and twisted configurations of multilayer graphene, using an ab initio approach combining density functional theory and the Wannier…

Mesoscale and Nanoscale Physics · Physics 2021-06-11 Nikita V. Tepliakov , QuanSheng Wu , Oleg V. Yazyev

For gapped graphene, we predict that an intense ultrashort (single-oscillation) circularly-polarized optical pulse can induce a large population of the conduction band and a large valley polarization. With an increase in the bandgap, the…

Mesoscale and Nanoscale Physics · Physics 2019-09-25 S. Azar Oliaei Motlagh , Fatemeh Nematollahi , Vadym Apalkov , Mark I. Stockman

Effects of disorder and valley polarization in graphene are investigated in the quantum Hall regime. We find anomalous localization properties for the lowest Landau level (LL), where disorder can induce wavefunction delocalization (instead…

Mesoscale and Nanoscale Physics · Physics 2008-02-21 Ana L. C. Pereira , P. A. Schulz