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We study the effects of insulating oxides in their crystalline forms on the energy band structure of monolayer and bilayer graphene using a \textit{first principles} density functional theory based electronic structure method and a local…

Materials Science · Physics 2011-12-09 Priyamvada Jadaun , Sanjay K. Banerjee , Leonard F. Register , Bhagawan Sahu

We study the retardation regime of doped graphene plasmons, given by the nominal crossing of the unretarded plasmon and light-cone. In addition to modifications in the plasmon dispersion relation, retardation implies strong coupling between…

Mesoscale and Nanoscale Physics · Physics 2012-08-16 G. Gómez-Santos , T. Stauber

The electronic properties of aluminum-doped graphenes enriched by multi-orbital hybridizations are investigated using first-principles calculations. The feature-rich electronic structures exhibit the quasi-rigid red shifts of the…

Materials Science · Physics 2016-06-07 Shih-Yang Lin , Yu-Tsung Lin , Ngoc Thanh Thuy Tran , Wu-Pei Su , Ming-Fa Lin

Strong 1D lattices usually lead to unconnected two-dimensional gases. The long-range character of the dipole-dipole interactions leads to a novel scenario where non-overlapping gases at different sites may interact significantly. We show…

Other Condensed Matter · Physics 2010-08-27 M. Klawunn , L. Santos

Plasmon are collective oscillations of mobile electrons with dynamics controlled by their charge stiffness("Drude weight"). Using terahertz spacetime metrology, we probe Plasmon dynamics of mono- and bi-layer graphene. In both systems, the…

We study the Dicke phase transition in a disordered system of emitters coupled to the plasmonic modes of a graphene monolayer. This system has unique properties associated with the tunable, dissipative and broadband characters of the…

Quantum Physics · Physics 2018-09-26 Yu-Xiang Zhang , Yuan Zhang , Klaus Mølmer

The collective excitation spectrum of two-dimensional (2D) antimonene is calculated beyond the low energy continuum approximation. The dynamical polarizability is computed using a 6-orbitals tight-binding model that properly accounts for…

Mesoscale and Nanoscale Physics · Physics 2018-11-14 Guus Slotman , Alexander Rudenko , Edo van Veen , Mikhail I. Katsnelson , Rafael Roldán , Shengjun Yuan

The energy spectrum of a system of Bose atoms in the superfluid phase in an optical lattice of the graphene type has been studied. The dispersion laws for the energy bands and the single particle spectral densities are calculated in the…

Quantum Gases · Physics 2014-11-21 I. V. Stasyuk , O. V. Velychko , I. R. Dulepa

In this paper we clarify the nature of $\pi$ and $\pi+\sigma$ electron excitations in pristine graphene. We clearly demonstrate the continuous transition from single particle to collective character of such excitations and how screening…

Materials Science · Physics 2015-12-16 Dino Novko , Vito Despoja , Marijan Šunjić

Electrons in isolated graphene layers are a two-dimensional gas of massless Dirac Fermions. In realistic devices, however, the electronic properties are modified by elastic deformations, interlayer coupling and substrate interaction. Here…

Accurate and simple local strain assessment in graphene is one of the crucial tasks in device characterization. Raman spectroscopy is often used for that purpose through monitoring of the G and 2D modes. However, the shifts of those two…

Materials Science · Physics 2018-04-27 Elena del Corro , Ladislav Kavan , Martin Kalbac , Otakar Frank

Interacting two-component Fermi gases loaded in a one-dimensional (1D) lattice and subject to harmonic trapping exhibit intriguing compound phases in which fluid regions coexist with local Mott-insulator and/or band-insulator regions.…

Strongly Correlated Electrons · Physics 2007-05-23 Gao Xianlong , M. Polini , B. Tanatar , M. P. Tosi

The effect of edge modification of armchair graphene nanoribbons (AGNRs) on the collective excitations are theoretically investigated. The tight-binding method is employed in conjunction with the dielectric function. Unconventional plasmon…

Mesoscale and Nanoscale Physics · Physics 2021-09-22 Thi-Nga Do , Po-Hsin Shih , Godfrey Gumbs , Danhong Huang

The electronic transport properties of graphene-based superlattice structures are investigated. A graphene-based modulation-doped superlattice structure geometry is proposed and consist of periodically arranged alternate layers:…

Mesoscale and Nanoscale Physics · Physics 2013-11-25 Dima Bolmatov , Chung-Yu Mou

We derive a material-realistic real-space many-body Hamiltonian for twisted bilayer graphene from first principles, including both single-particle hopping terms for $p_z$ electrons and long-range Coulomb interactions. By disentangling low-…

Mesoscale and Nanoscale Physics · Physics 2022-01-24 Tom Westerhout , Mikhail I. Katsnelson , Malte Rösner

Superlattices from twisted graphene mono- and bi-layer systems give rise to on-demand many-body states such as Mott insulators and unconventional superconductors. These phenomena are ascribed to a combination of flat bands and strong…

We present a theoretical study of the local optical conductivity, plasmon spectra, and thermoelectric properties of twisted bilayer graphene (TBG) at different filling factors and twist angles $\theta$. Our calculations are based on the…

Mesoscale and Nanoscale Physics · Physics 2020-09-04 Pietro Novelli , Iacopo Torre , Frank H. L. Koppens , Fabio Taddei , Marco Polini

We study the localization properties of the wavefunctions in graphene flakes with short range disorder, via the numerical calculation of the Inverse Participation Ratio($IPR$) and it scaling which provides the fractal dimension $D_{2}$. We…

Mesoscale and Nanoscale Physics · Physics 2014-02-21 Ioannis Kleftogiannis , Ilias Amanatidis

We calculate the static polarizability of multilayer graphene and study the effect of stacking arrangement, carrier density, and onsite energy difference on graphene screening properties. At low densities, the energy spectrum of multilayer…

Materials Science · Physics 2012-08-14 Hongki Min , E. H. Hwang , S. Das Sarma

Gapless spectrum of graphene allows easy spatial separation of electrons and holes with an external in-plane electric field. Guided collective plasmon modes can propagate along the separation line, whose amplitude decays with the distance…

Mesoscale and Nanoscale Physics · Physics 2012-05-23 N. M. Hassan , V. V. Mkhitaryan , E. G. Mishchenko