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Related papers: Valley separation via trigonal warping

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Zeeman effect induced by the magnetic field introduces a splitting between the two valleys at K$^+$ and K$^-$ points of the Brillouin zone in monolayer semiconducting transition metal dichalcogenides. In consequence, the photoluminescence…

Mesoscale and Nanoscale Physics · Physics 2020-12-30 Tomasz Smoleński , Tomasz Kazimierczuk , Mateusz Goryca , Karol Nogajewski , Marek Potemski , Piotr Kossacki

Control over minivalley polarization and interlayer coupling is demonstrated in double bilayer graphene twisted with an angle of 2.37$^\circ$. This intermediate angle is small enough for the minibands to form and large enough such that the…

A theory based on localized-orbital approaches is developed to describe the valley splitting observed in silicon quantum wells. The theory is appropriate in the limit of low electron density and relevant for proposed quantum computing…

Two-dimensional semimetals with tilted Dirac cones in the electronic band structure are shown to exhibit spatial separation of carriers belonging to different valleys under illumination. In stark contrast to gapped Dirac materials this…

Mesoscale and Nanoscale Physics · Physics 2023-11-08 A. Wild , E. Mariani , M. E. Portnoi

In topological photonics, artificial photonic structures are constructed for realizing nontrivial unidirectional propagation of photonic information. On the other hand, moir\'e superlattices are emerging as an important avenue for…

Optics · Physics 2024-03-13 Weiwei Luo , Jiang Fan , Alexey B. Kuzmenko , Wei Cai , Jingjun Xu

Intrinsic and extrinsic valley Hall effects are predicted to emerge in graphene systems with uniform or spatially-varying mass terms. Extrinsic mechanisms, mediated by the valley-dependent scattering of electrons at the Fermi surface, can…

Mesoscale and Nanoscale Physics · Physics 2021-07-07 Fionnuala Solomon , Stephen R. Power

Achieving a population imbalance between the two inequivalent valleys is a critical first step for any valleytronic device. A valley-polarization can be induced in biased bilayer graphene using circularly polarized light. In this paper, we…

Mesoscale and Nanoscale Physics · Physics 2021-02-17 Alex Friedlan , Marc M. Dignam

Valley polarized topological kink states, existing broadly in the domain wall of hexagonal lattices systems, are identified in experiments, unfortunately, only very limited physical properties being given. Using an Aharanov-Bohm…

Mesoscale and Nanoscale Physics · Physics 2018-10-17 Shu-guang Cheng , Haiwen Liu , Hua Jiang , Qing-Feng Sun , X. C. Xie

We derive the angular generation density of photoexcited carriers in gapless and gapped Bernal bilayer graphene. Exploiting the strong anisotropy of the band structure of bilayer graphene at low energies due to trigonal warping, we show…

Mesoscale and Nanoscale Physics · Physics 2024-09-16 T. J. Osborne , M. E. Portnoi , E. Mariani

Interfacing atomically thin van der Waals semiconductors with magnetic substrates enables additional control on their intrinsic valley degree of freedom and provides a promising platform for the development of novel valleytronic devices for…

Lifting the valley degeneracy is an efficient way to achieve valley polarization for further valleytronics operations. In this work, we demonstrate that a large valley splitting can be obtained in monolayer transition metal dichalcogenides…

Materials Science · Physics 2018-01-17 Lei Xu , Ming Yang , Lei Shen , Jun Zhou , Tao Zhu , Yuan Ping Feng

We discuss valley current, which is carried by quasiparticles in graphene. We show that the valley current arises owing to a peculiar term in the electron-phonon collision integral that mixes the scalar and vector gauge-field-like vertices…

Mesoscale and Nanoscale Physics · Physics 2023-05-10 Ankang Liu , Alexander M. Finkel'stein

We propose a device for the generation of valley polarized electronic current in bilayer graphene. By analyzing the response of this material to intense terahertz frequency light in the presence of a transverse electric field, we…

Mesoscale and Nanoscale Physics · Physics 2009-08-20 D. S. L. Abergel , Tapash Chakraborty

We show that valley degeneracy in rotationally faulted multilayer graphene may be broken in the presence of a magnetic field and interlayer commensurations. This happens due to a simultaneous breaking of both time-reversal and inversion…

Mesoscale and Nanoscale Physics · Physics 2015-06-17 Hridis K Pal , E. J. Mele , M. Kindermann

Graphene pn junction is the brick to build up variety of graphene nano-structures. The analytical formula of the conductance of graphene gradual pn junctions in the whole bipolar region has been absent up to now. In this paper, we…

Mesoscale and Nanoscale Physics · Physics 2016-01-07 Mou Yang , Rui-Qiang Wang , Yan-Kui Bai

We theoretically study valley-filtering in pristine graphene irradiated by bicircular counter-rotating laser drive. The dynamical symmetry of the graphene and laser drive disrupts graphene's inversion symmetry, which results distinct…

Mesoscale and Nanoscale Physics · Physics 2024-01-23 Rekha Kumari , Gopal Dixit , Arijit Kundu

We study spatial symmetry in general ABA-stacked multilayer graphene to illustrate how electronic spectra at the two valleys are related in a magnetic field. We show that the lattice of multilayers with an even number of layers, as well as…

Mesoscale and Nanoscale Physics · Physics 2015-05-14 Mikito Koshino , Edward McCann

In bilayer graphene, electrostatic confinement can be realized by a suitable design of top and back gate electrodes. We measure electronic transport through a bilayer graphene quantum dot, which is laterally confined by gapped regions and…

Introducing quantum confinement has uncovered a rich set of interesting quantum phenomena and allows one to directly probe the physics of confined (quasi-)particles. In most experiments, however, electrostatic potential is the only…

Mesoscale and Nanoscale Physics · Physics 2024-03-08 Ya-Ning Ren , Yu-Chen Zhuang , Qing-Feng Sun , Lin He

We investigate the valley relaxation due to intervalley coupling in a single-electron bilayer graphene quantum dot. The valley relaxation is assisted by both the emission of acoustic phonons via the deformation potential and bond-length…

Mesoscale and Nanoscale Physics · Physics 2024-02-29 Lin Wang , Guido Burkard