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In this review, we present recent works on materials whose common point is the presence of electronic bands of very low dispersion, called "flat bands", which are due to specific atomic order effects without electron interactions. These…

We present the first observations of zero-n bandgaps in photonic crystal superlattices consisting of alternating stacks of negative index photonic crystals and positive index dielectric materials in the near-infrared. Guided by ab initio…

Developing graphene-based nanoelectronics hinges on opening a band gap in the electronic structure of graphene, which is commonly achieved by breaking the inversion symmetry of the graphene lattice via an electric field (gate bias) or…

Materials Science · Physics 2014-06-11 Liangzhi Kou , Feiming Hu , Binghai Yan , Thomas Frauenheim , Changfeng Chen

We combined periodic ripples and electrostatic potentials to form curved graphene superlattices and studied the effects of space-dependent Fermi velocity induced from curvature on their electronic properties. With equal periods and…

Mesoscale and Nanoscale Physics · Physics 2021-06-29 Jianli Luan , Kaiyi Guo , Shangyang Li , Tianxing Ma , Li-Gang Wang , Hai-Qing Lin

Graphene revealed a number of unique properties beneficial for electronics. However, graphene does not have an energy band-gap, which presents a serious hurdle for its applications in digital logic gates. The efforts to induce a band-gap in…

Mesoscale and Nanoscale Physics · Physics 2015-06-16 Guanxiong Liu , Sonia Ahsan , Alexander G. Khitun , Roger K. Lake , Alexander A. Balandin

In this Letter, we derive an effective theory of graphene on a hexagonal Boron Nitride (h-BN) substrate. We show that the h-BN substrate generically opens a spectral gap in graphene despite the lattice mismatch. The origin of that gap is…

Mesoscale and Nanoscale Physics · Physics 2012-11-12 M. Kindermann , Bruno Uchoa , D. L. Miller

Graphene has shown great application potentials as the host material for next generation electronic devices. However, despite its intriguing properties, one of the biggest hurdles for graphene to be useful as an electronic material is its…

The role of defect-induced zero-energy modes on charge transport in graphene is investigated using Kubo and Landauer transport calculations. By tuning the density of random distributions of monovacancies either equally populating the two…

Mesoscale and Nanoscale Physics · Physics 2013-05-13 Alessandro Cresti , Frank Ortmann , Thibaud Louvet , Dinh Van Tuan , Stephan Roche

In the effective mass approximation, electronic property in graphene can be characterized by the relativistic Dirac equation. Within such a continuum model we investigate the electronic transport through graphene waveguides formed by…

Strongly Correlated Electrons · Physics 2015-05-13 Haidong Li , Lin Wang , Zhihuan Lan , Yisong Zheng

We introduce graphene antidot lattice waveguides: nanostructured graphene where a region of pristine graphene is sandwiched between regions of graphene antidot lattices. The band gap in the surrounding antidot lattices enable localized…

Mesoscale and Nanoscale Physics · Physics 2013-06-11 Jesper Goor Pedersen , Tue Gunst , Troels Markussen , Thomas Garm Pedersen

The superconducting state and mechanism are among the least understood phenomena in twisted graphene systems. For instance, recent tunneling experiments indicate a transition between nodal and gapped pairing with electron filling, which is…

Superconductivity · Physics 2023-11-17 Maine Christos , Subir Sachdev , Mathias S. Scheurer

The mode-dependent transmission of relativistic ballistic massless Dirac fermion through a graphene based double barrier structure is being investigated for various barrier parameters. We compare our results with already published work and…

Mesoscale and Nanoscale Physics · Physics 2015-05-28 Ahmed Jellal , El Bouazzaoui Choubabi , Hocine Bahlouli , Abdullah Aljaafari

We introduce the idea that the electronic band structure of a charge density wave system may mimic the electronic structure of graphene. In that case a class of materials quite different from graphene might be opened up to exploit…

Mesoscale and Nanoscale Physics · Physics 2017-11-22 John M. Vail , Oscar J. Hernandez , Ming-Su Si , Zhoufei Wang

We investigate the emergence of extra Dirac points in the electronic structure of a periodically spaced barrier system, i.e., a superlattice, on single-layer graphene, using a Dirac-type Hamiltonian. Using square barriers allows us to find…

Mesoscale and Nanoscale Physics · Physics 2015-05-18 M. Barbier , P. Vasilopoulos , F. M. Peeters

Recent experimental findings and theoretical predictions suggest that nitrogen-doped CVD-grown graphene may give rise to electronic band gaps due to impurity distributions which favour segregation on a single sublattice. Here we demonstrate…

Mesoscale and Nanoscale Physics · Physics 2016-02-09 Thomas Aktor , Antti-Pekka Jauho , Stephen R. Power

We propose a first principles effective medium formalism to study the propagation of electron waves in semiconductor heterostructures with a zero-band gap. Our theory confirms that near the K-point the dynamics of a two-dimensional electron…

Mesoscale and Nanoscale Physics · Physics 2016-10-20 Sylvain Lannebère , Mário G. Silveirinha

High mobility single and few-layer graphene sheets are in many ways attractive as nanoelectronic circuit hosts but lack energy gaps, which are essential to the operation of field-effect transistors. One of the methods used to create gaps in…

Mesoscale and Nanoscale Physics · Physics 2018-12-26 Hakseong Kim , Nicolas Leconte , Bheema L. Chittari , Kenji Watanabe , Takashi Taniguchi , Allan H. MacDonald , Jeil Jung , Suyong Jung

The structures and electron properties of new superlattices formed on graphene by adsorbed hydrogen molecules are theoretically described. It has been shown that superlattices of the (n, 0) zigzag type with linearly arranged pairs of H…

Materials Science · Physics 2007-05-23 L. A. Chernozatonskii , P. B. Sorokin , E. E. Belova , J. Bruning , A. S. Fedorov

We study the optical conductivity of a doped graphene when a sublattice symmetry breaking is occurred in the presence of the electron-phonon interaction. Our study is based on the Kubo formula that is established upon the retarded…

Mesoscale and Nanoscale Physics · Physics 2015-05-14 Kh. Jahanbani , Reza Asgari

An exact expression of the transmission probability through a finite graphene superlattice with an arbitrary number of potential barriers $n$ is derived in two cases of the periodic potential: rectangular electric potential and…

Mesoscale and Nanoscale Physics · Physics 2015-02-20 C. Huy Pham , V. Lien Nguyen