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Related papers: Screening and collective modes in gapped bilayer g…

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For atomic thin layer insulating materials we provide an exact analytic form of the two-dimensional screened potential. In contrast to three-dimensional systems where the macroscopic screening can be described by a static dielectric…

Mesoscale and Nanoscale Physics · Physics 2015-05-27 Pierluigi Cudazzo , Ilya V. Tokatly , Angel Rubio

The line shape of the double-resonant $2D$ Raman mode in bilayer graphene is often considered to be characteristic for a certain laser excitation energy. Here, in a joint experimental and theoretical study, we analyze the dependence of the…

Mesoscale and Nanoscale Physics · Physics 2018-12-19 Felix Herziger , Christoph Tyborski , Oliver Ochedowski , Marika Schleberger , Janina Maultzsch

Recent observations of superconductivity in Moire graphene have lead to an intense interest in that system, with subsequent studies revealing a more complex phase diagram including correlated insulators and ferromagnetic phases. Here we…

Strongly Correlated Electrons · Physics 2023-05-10 Z. E. Krix , O. P. Sushkov

Screening is one of the fundamental concepts in solid state physics. It has a great impact on the electronic properties of graphene where huge mobilities were observed in spite of the large concentration of charged impurities. While static…

Mesoscale and Nanoscale Physics · Physics 2014-03-18 Marinko Jablan , Marin Soljacic , Hrvoje Buljan

Kohn anomalies in three-dimensional metallic crystals are dips in the phonon dispersion that are caused by abrupt changes in the screening of the ion-cores by the surrounding electron-gas. These anomalies are also present at the…

Mesoscale and Nanoscale Physics · Physics 2013-11-19 F. Forster , A. Molina-Sanchez , S. Engels , A. Epping , K. Watanabe , T. Taniguchi , L. Wirtz , C. Stampfer

In this work we show that the trigonal warping of the electronic bands in bilayer graphene dramatically modifies the behavior of the one-dimensional modes topologically confined due to an inhomogeneous bias that changes sign across a…

Mesoscale and Nanoscale Physics · Physics 2011-07-19 A. S. Núñez , E. Suárez Morell , P. Vargas

A fully selfconsistent treatment for gap generation and Coulomb screening in excitonic insulators is presented. The method is based on the equations of motion for the relevant dynamical variables combined with a variational approach.…

Mesoscale and Nanoscale Physics · Physics 2013-06-27 Tineke Stroucken , Johanna H. Grönqvist , Stephan. W. Koch

We study the effects of disorder on bilayer graphene using four different microscopic models and directly compare their results. We compute the self-energy, density of states, and optical conductivity in the presence of short-ranged…

Mesoscale and Nanoscale Physics · Physics 2012-01-27 D. S. L. Abergel , Hongki Min , E. H. Hwang , S. Das Sarma

Based on the full Hamiltonian of bilayer graphene, phase transitions are realized by the change of the in-plane magnetic field and the electrical bias in bilayer graphene. We show that the engineering of Chern numbers of four bands is…

Mesoscale and Nanoscale Physics · Physics 2024-05-24 Narjes Kheirabadi

By computing the double-resonant Raman scattering cross-section completely from first principles and including electron-electron interaction at the $GW$ level, we unravel the dominant contributions for the double-resonant 2D-mode in bilayer…

Mesoscale and Nanoscale Physics · Physics 2014-11-04 Felix Herziger , Matteo Calandra , Paola Gava , Patrick May , Michele Lazzeri , Francesco Mauri , Janina Maultzsch

We analyze the response of bilayer graphene to an external transverse electric field using a variational method. A previous attempt to do so in a recent paper by Falkovsky [Phys. Rev. B 80, 113413 (2009)] is shown to be flawed. Our…

Mesoscale and Nanoscale Physics · Physics 2011-08-17 M. M. Fogler , E. McCann

Bilayer graphene is a highly promising material for electronic and optoelectronic applications since it is supporting massive Dirac fermions with a tuneable band gap. However, no consistent picture of the gap's effect on the optical and…

In recent years, interesting materials have emerged which are only available as micron-scale flakes, and whose novel physics might be better understood through broadband microwave spectroscopy; examples include twisted bilayer graphene [1],…

Mesoscale and Nanoscale Physics · Physics 2022-06-08 Antonio Levy , Neil Zimmerman

The microscopic pairing mechanism for superconductivity in magic-angle twisted bilayer graphene remains an open question. Recent experimental studies seem to rule out a purely electronic mechanism due to the insensitivity of the critical…

Superconductivity · Physics 2024-03-19 Liangtao Peng , Indra Yudhistira , Giovanni Vignale , Shaffique Adam

Bernal-stacked bilayer graphene (BLG) provides an ideal basis for gate-controlled, and free of etching, electronic devices. Theoretical modeling of realistic devices is an essential part of research, however, simulations of large-scale BLG…

Mesoscale and Nanoscale Physics · Physics 2024-08-16 Szu-Chao Chen , Alina Mreńca-Kolasińska , Ming-Hao Liu

Graphene-based heterostructures display a variety of phenomena that are strongly tunable by electrostatic local gates. Monolayer graphene (MLG) exhibits tunable surface plasmon polaritons, as revealed by scanning nano-infrared experiments.…

Bilayer graphene (BLG) has recently attracted a great deal of attention because of its electrically tunable energy gaps and its unusual electronic structure. In this Letter we present analytical and semi-analytical expressions, based on the…

Strongly Correlated Electrons · Physics 2009-12-03 Giovanni Borghi , Marco Polini , Reza Asgari , A. H. MacDonald

Bilayer graphene is a recently isolated and intriguing class of many-body systems with massive chiral quasiparticles. We present theoretical results for the electronic compressibility of bilayer graphene that are based on a four-band…

Mesoscale and Nanoscale Physics · Physics 2010-10-06 Giovanni Borghi , Marco Polini , Reza Asgari , A. H. MacDonald

The most important bands for the evaluation of strain in graphene (the 2D and 2D prime modes) are investigated. It is shown that for Bernal-stacked bilayers, the two-phonon Raman features have three different components that can be assigned…

Materials Science · Physics 2021-07-27 Sara D Costa , Johan Ek Weis , Otakar Frank , Michaela Fridrichová , Martin Kalbac

The Raman shift, broadening, and relative Raman intensities of bilayer graphene are computed as functions of the electron concentration. We include dynamic effects for the phonon frequencies and we consider the gap induced in the band…

Materials Science · Physics 2009-09-11 Paola Gava , Michele Lazzeri , A. Marco Saitta , Francesco Mauri