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Related papers: Floquet-Engineered Valley-Topotronics in Kekul\'e-…

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Recent experiments by Guti\'errez $\textit{et al.}$ [Nature Phys. $\textbf{12}$, 950 (2016)] on a graphene-copper superlattice have revealed an unusual Kekul\'e bond texture in the honeycomb lattice --- a Y-shaped modulation of weak and…

Mesoscale and Nanoscale Physics · Physics 2018-02-12 O. V. Gamayun , V. P. Ostroukh , N. V. Gnezdilov , İ. Adagideli , C. W. J. Beenakker

Electromagnetic dressing by a high-frequency field drastically modifies the electronic transport properties on Dirac systems. Here its effects on the energy spectrum of graphene with two possible phases of Kekul\'e distortion (namely, Kek-Y…

Mesoscale and Nanoscale Physics · Physics 2020-10-07 M. A. Mojarro , V. G. Ibarra-Sierra , J. C. Sandoval-Santana , R. Carrillo-Bastos , Gerardo G. Naumis

In graphene, a Kekul\'e-Y bond texture modifies the electronic band structure generating two concentric Dirac cones with different Fermi velocities lying in the {\Gamma}-point in reciprocal space. The energy dispersion results in different…

Mesoscale and Nanoscale Physics · Physics 2022-11-23 Elias Andrade , Ramon Carrillo-Bastos , Mahmoud M. Asmar , Gerardo G. Naumis

Valley degrees of freedom offer a potential resource for quantum information processing if they can be effectively controlled. We discuss an optical approach to this problem in which intense light breaks electronic symmetries of a…

Mesoscale and Nanoscale Physics · Physics 2016-01-11 Arijit Kundu , H. A. Fertig , Babak Seradjeh

A Kekul\'e bond texture in graphene modifies the electronic band structure by folding the Brillouin zone and bringing the two inequivalent Dirac points to the center. This can result, in the opening of a gap (Kek-O) or the locking of the…

Mesoscale and Nanoscale Physics · Physics 2019-01-16 Elias Andrade , Ramon Carrillo-Bastos , Gerardo G. Naumis

Graphene deposited on top of a Copper(111) substrate may develop a Y-shaped Kekul\'e bond texture (Kekul\'e-Y), locking the momentum of its Dirac fermions with its valley degree of freedom. As a consequence, the valley degeneracy of its…

Mesoscale and Nanoscale Physics · Physics 2022-05-05 Alex Santacruz , Priscilla E. Iglesias , Ramon Carrillo-Bastos , Francisco Mireles

Graphene's electronic structure can be fundamentally altered when a substrate- or adatom-induced Kekul\'e superlattice couples the valley and isospin degrees of freedom. Here, we show that the band structure of Kekul\'e-textured graphene…

Mesoscale and Nanoscale Physics · Physics 2019-09-04 David A. Ruiz-Tijerina , Elias Andrade , Ramon Carrillo-Bastos , Francisco Mireles , Gerardo G. Naumis

This work investigates the Floquet dynamics of electrons and excitons (particle-hole pairs) in a Dirac material referred to as Kekul\'e-distorted graphene. Specifically, we examine the role played by a high frequency driving electromagnetic…

Mesoscale and Nanoscale Physics · Physics 2026-02-12 Sita Kandel , Godfrey Gumbs

Driving quantum materials out-of-equilibrium makes it possible to generate states of matter inaccessible through standard equilibrium tuning methods. Upon time-periodic coherent driving of electrons using electromagnetic fields, the…

We propose a scheme to trap and filter electrons, valley dependently, on a scale beyond the diffraction limit, in a gapped Dirac system using a circularly polarized light beam and a microscale metallic resonator. The main mechanism allowing…

Mesoscale and Nanoscale Physics · Physics 2019-01-23 Kevin Dini , Ivan V. Iorsh , Andrey Bogdanov , Ivan A. Shelykh

We study the interplay between a Kekul\'e patterned distortion in monolayer graphene and a monochromatic laser irradiation, focusing in the long wavelength approximation of its Landau level structure. Exploiting the symmetries of the…

Mesoscale and Nanoscale Physics · Physics 2023-03-06 A. López , F. Mireles

The transport properties of electrons in graphene $p$-$n$ junction with uniform Kekul\'e lattice distortion have been studied using the tight-binding model and the Landauer-B\"uttiker formalism combined with the nonequilibrium Green's…

Mesoscale and Nanoscale Physics · Physics 2023-07-19 Peipei Zhang , Chao Wang , Yu-Xian Li , Lixue Zhai , Juntao Song

Generating and manipulating Dirac points in artificial atomic crystals has received attention especially in photonic systems due to their ease of implementation. In this paper, we propose a two-dimensional photonic crystal made of a…

Optics · Physics 2021-09-15 R. Zhou , H. Lin , Y. Liu , X. Shi , R. Tang , Y. Wu , Z. Yu

Analogous to charge and spin, electrons in solids endows an additional degree of freedom: the valley pseudospin. Two-dimensional hexagonal materials such as graphene exhibit two valleys, labelled as $\mathbf{K}$ and $\mathbf{K}^{\prime}$.…

Mesoscale and Nanoscale Physics · Physics 2022-01-12 M. S. Mrudul , Gopal Dixit

Inversion symmetry breaking allows contrasted circular dichroism in different k-space regions, which takes the extreme form of optical selection rules for interband transitions at high symmetry points. In materials where band-edges occur at…

Mesoscale and Nanoscale Physics · Physics 2008-06-05 Wang Yao , Di Xiao , Qian Niu

Within the first principle calculations, we propose a boron and nitrogen cluster incorporated graphene system for efficient valley polarization. The broken spatial inversion symmetry results in high Berry curvature at K and K' valleys of…

Materials Science · Physics 2024-04-18 Shneha Biswas , Souren Adhikary , Sudipta Dutta

We investigate the topological properties of Floquet-engineered twisted bilayer graphene above the magic angle driven by circularly polarized laser pulses. Employing a full Moir\'e-unit-cell tight-binding Hamiltonian based on…

Materials Science · Physics 2019-09-30 Gabriel E. Topp , Gregor Jotzu , James W. McIver , Lede Xian , Angel Rubio , Michael A. Sentef

We introduce a generalized Hamiltonian describing not only all topological phases observed experimentally in Kekul\'e graphene (KekGr) but predicting also new ones. These phases show features like a quadratic band crossing point, valley…

Mesoscale and Nanoscale Physics · Physics 2021-11-12 Santiago Galván y García , Thomas Stegmann , Yonatan Betancur-Ocampo

Dirac electrons in graphene have a valley degree of freedom that is being explored as a carrier of information. In that context of "valleytronics" one seeks to coherently manipulate the valley index. Here we show that reflection from a…

Mesoscale and Nanoscale Physics · Physics 2018-09-12 C. W. J. Beenakker , N. V. Gnezdilov , E. Dresselhaus , V. P. Ostroukh , Y. Herasymenko , I. Adagideli , J. Tworzydlo

Graphene on hexagonal boron nitride (hBN) can exhibit a topological phase via mutual crystallographic alignment. Recent measurements of nonlocal resistance ($R_{nl}$) near the secondary Dirac point (SDP) in ballistic graphene/hBN…

Mesoscale and Nanoscale Physics · Physics 2020-12-21 Yang Li , Mario Amado , Timo Hyart , Grzegorz P. Mazur , Jason W. A. Robinson
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