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We introduce a two-dimensional model of spin-1/2 Dirac fermions in graphene subjected to a highly tunable electric field, which exhibits super-Klein tunneling. The electric field can be continuously interpolated between two limiting…

Mesoscale and Nanoscale Physics · Physics 2026-03-24 Alonso Contreras-Astorga , Francisco Correa , Luis Inzunza , Vit Jakubsky , Raul Valencia-Torres

To understand the band bending caused by metal contacts, we study the potential and charge density induced in graphene in response to contact with a metal strip. We find that the screening is weak by comparison with a normal metal as a…

Materials Science · Physics 2015-05-14 P. A. Khomyakov , A. A. Starikov , G. Brocks , P. J. Kelly

Van der Waals structures formed by aligning monolayer graphene with insulating layers of hexagonal boron nitride exhibit a moir\'e superlattice that is expected to break sublattice symmetry. Despite an energy gap of several tens of…

Brownian dynamics of Dirac fermions in twisted bilayer graphene is investigated within the framework of semiclassical relativistic Langevin equations. We find that under the influence of orthogonal, commensurate ac drives in the periodic…

Mesoscale and Nanoscale Physics · Physics 2023-08-31 Abdullah Yar

We analyze by exact Renormalization Group (RG) methods the infrared properties of an effective model of graphene, in which two-dimensional massless Dirac fermions propagating with a velocity smaller than the speed of light interact with a…

Strongly Correlated Electrons · Physics 2011-01-25 Alessandro Giuliani , Vieri Mastropietro , Marcello Porta

We find exact states of graphene quasiparticles under a time-dependent deformation (sound wave), whose propagation velocity is smaller than the Fermi velocity. To solve the corresponding effective Dirac equation, we adapt the Volkov-like…

Mesoscale and Nanoscale Physics · Physics 2017-02-09 M. Oliva-Leyva , G. G. Naumis

We reveal that optical saturation of the low-energy states takes place in graphene for arbitrarily weak electromagnetic fields. This effect originates from the diverging field-induced interband coupling at the Dirac point. Using…

Mesoscale and Nanoscale Physics · Physics 2024-01-02 Behrooz Semnani , Roland Jago , Safieddin Safavi-Naeini , Amir Hamed Majedi , Ermin Malic , Philippe Tassin

The transmission T and conductance G through one or multiple one-dimensional, delta-function barriers of two-dimensional fermions with a linear energy spectrum are studied. T and G are periodic functions of the strength P of the…

Mesoscale and Nanoscale Physics · Physics 2009-11-23 M. Barbier , P. Vasilopoulos , F. M. Peeters

We investigate spin transport through ferromagnetic graphene vertical heterostructures where a sandwiched tunneling layer is either a normal or ferroelectric insulator. We show that the spin-polarization of the tunneling current is…

Mesoscale and Nanoscale Physics · Physics 2016-05-31 Nojoon Myoung , Hee Chul Park , Seung Joo Lee

Ballistic electrons in solids can have mean free paths far larger than the smallest features patterned by lithography. This has allowed development and study of solid-state electron-optical devices such as beam splitters and quantum point…

Mesoscale and Nanoscale Physics · Physics 2017-05-24 Arthur W. Barnard , Alex Hughes , Aaron L. Sharpe , Kenji Watanabe , Takashi Taniguchi , David Goldhaber-Gordon

The recent discovery of superconductivity in magic-angle twisted bilayer graphene has sparked a renewed interest in the strongly-correlated physics of $sp^2$ carbons, in stark contrast to preliminary investigations which were dominated by…

Mesoscale and Nanoscale Physics · Physics 2023-02-17 Deepanshu Aggarwal , Rohit Narula , Sankalpa Ghosh

We explore the optical properties of periodic layered media containing left-handed metamaterials. This study is based on several analogies between the propagation of light in metamaterials and charge transport in graphene. We derive the…

Optics · Physics 2013-08-09 Yury P. Bliokh , Valentin Freilikher , Franco Nori

The chemical stability of graphene and other free-standing two-dimensional crystals means that they can be stacked in different combinations to produce a new class of functional materials, designed for specific device applications. Here we…

Mesoscale and Nanoscale Physics · Physics 2013-05-03 L. Britnell , R. V. Gorbachev , A. K. Geim , L. A. Ponomarenko , A. Mishchenko , M. T. Greenaway , T. M. Fromhold , K. S. Novoselov , L. Eaves

Ballistic semiconductor structures have allowed the realization of optics-like phenomena in electronics, including magnetic focusing and lensing. An extension that appears unique to graphene is to use both n and p carrier types to create…

Mesoscale and Nanoscale Physics · Physics 2011-04-27 J. R. Williams , Tony Low , M. S. Lundstrom , C. M. Marcus

We study the interaction of graphene with ultrashort few femtosecond long optical pulse. For such a short pulse, the electron dynamics is coherent and is described within the tight-binding model of graphene. The interaction of optical pulse…

Mesoscale and Nanoscale Physics · Physics 2014-01-23 Hamed Koochaki Kelardeh , Vadym Apalkov , Mark I. Stockman

We calculate the dynamic polarizability under the random phase approximation for the dice lattice. This two-dimensional system gives rise to massless Dirac fermions with pseudospin-1 in the low-energy quantum excitation spectrum, providing…

Mesoscale and Nanoscale Physics · Physics 2016-05-04 John D. Malcolm , Elisabeth J. Nicol

Electrons and holes in clean, charge-neutral graphene behave like a strongly coupled relativistic liquid. The thermo-electric transport properties of the interacting Dirac quasiparticles are rather special, being constrained by an emergent…

Strongly Correlated Electrons · Physics 2017-08-23 Markus Mueller , Lars Fritz , Subir Sachdev , Joerg Schmalian

Plasmons, which are collective charge oscillations, offer the potential to use optical signals in nano-scale electric circuits. Recently, plasmonics using graphene have attracted interest, particularly because of the tunable plasmon…

Mesoscale and Nanoscale Physics · Physics 2015-06-04 N. Kumada , S. Tanabe , H. Hibino , H. Kamata , M. Hashisaka , K. Muraki , T. Fujisawa

A near-field scanning optical microscope is used to locally induce photocurrent in a graphene transistor with high spatial resolution. By analyzing the spatially resolved photo-response, we find that in the n-type conduction regime a p-n-p…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 T. Mueller , F. Xia , M. Freitag , J. Tsang , Ph. Avouris

Disordered Fermi-Dirac distributions are used to model, within a straightforward and essentially phenomenological Boltzmann equation approach, the electron/hole transport across graphene puddles. We establish, with striking experimental…

Mesoscale and Nanoscale Physics · Physics 2015-05-30 L. Moriconi , D. Niemeyer