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City University of New York (CUNY)

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Graphene

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Full-Text Articles in Physical Sciences and Mathematics

Plasmon Damping Rates In Coulomb-Coupled 2d Layers In A Heterostructure, Dipendra Dahal, Godfrey Gumbs, Andrii Iurov, Chin-Sen Ting Nov 2022

Plasmon Damping Rates In Coulomb-Coupled 2d Layers In A Heterostructure, Dipendra Dahal, Godfrey Gumbs, Andrii Iurov, Chin-Sen Ting

Publications and Research

The Coulomb excitations of charge density oscillation are calculated for a double-layer heterostructure. Specifically, we consider two-dimensional (2D) layers of silicene and graphene on a substrate. From the obtained surface response function, we calculated the plasmon dispersion relations, which demonstrate how the Coulomb interaction renormalizes the plasmon frequencies. Most importantly, we have conducted a thorough investigation of how the decay rates of the plasmons in these heterostructures are affected by the Coulomb coupling between different types of two- dimensional materials whose separations could be varied. A novel effect of nullification of the silicene band gap is noticed when graphene is …


Giant Acoustically-Induced Synthetic Hall Voltages In Graphene, Pai Zhao, Chithra H. Sharma, Renrong Liang, Christian Glasenapp, Lev Mourokh, Vadim M. Kovalev, Patrick Huber, Marta Prada, Lars Tiemann, Robert H. Blick Jan 2022

Giant Acoustically-Induced Synthetic Hall Voltages In Graphene, Pai Zhao, Chithra H. Sharma, Renrong Liang, Christian Glasenapp, Lev Mourokh, Vadim M. Kovalev, Patrick Huber, Marta Prada, Lars Tiemann, Robert H. Blick

Publications and Research

Any departure from graphene’s flatness leads to the emergence of artificial gauge fields that act on the motion of the Dirac fermions through an associated pseudomagnetic field. Here, we demonstrate the tunability of strong gauge fields in nonlocal experiments using a large planar graphene sheet that conforms to the deformation of a piezoelectric layer by a surface acoustic wave. The acoustic wave induces a longitudinal and a giant synthetic Hall voltage in the absence of external magnetic fields. The superposition of a synthetic Hall potential and a conventional Hall voltage can annihilate the sample’s transverse potential at large external magnetic …


Strain‑Induced Quantum Hall Phenomena Of Excitons In Graphene, Oleg L. Berman, Roman Ya. Kezerashvili, Yurii E. Lozovik, Klaus G. Ziegler Jan 2022

Strain‑Induced Quantum Hall Phenomena Of Excitons In Graphene, Oleg L. Berman, Roman Ya. Kezerashvili, Yurii E. Lozovik, Klaus G. Ziegler

Publications and Research

We study direct and indirect pseudomagnetoexcitons, formed by an electron and a hole in the layers of gapped graphene under strain‑induced gauge pseudomagnetic field. Since the train‑induced pseudomagnetic field acts on electrons and holes the same way, it occurs that the properties of single pseudomagnetoexcitons, their collective effects and phase diagram are cardinally different from those of magnetoexcitons in a real magnetic field. We have derived wave functions and energy spectrum of direct in a monolayer and indirect pseudomagnetoexcitons in a double layer of gapped graphene. The quantum Hall effect for direct and indirect excitons was predicted in the monolayers …


Kinetic Study Of The Oxygen Reduction Reaction On Α-Ni(Oh)2 And Α-Ni(Oh)2 Supported On Graphene Oxide, Elaheh Farjami, L. Jay Deiner Jun 2015

Kinetic Study Of The Oxygen Reduction Reaction On Α-Ni(Oh)2 And Α-Ni(Oh)2 Supported On Graphene Oxide, Elaheh Farjami, L. Jay Deiner

Publications and Research

The kinetics of the oxygen reduction reaction on α-Ni(OH)2 and α-Ni(OH)2 supported on graphene oxide (α-Ni(OH)2/GO) were investigated using rotating disk linear sweep voltammetry in alkaline solutions of varying oxygen and hydroxyl concentrations. Over the full hydroxyl concentration range (0.05 M to 0.5M), α-Ni(OH)2/GO displayed higher activity than unsupported α-Ni(OH)2. The electron transfer numbers were 2.9 ± 0.2 for α-Ni(OH)2, 3.4 ± 0.1 for α-Ni(OH)2/GO at low [OH−], and 3.8–3.9 for α-Ni(OH)2/GO at high [OH−]. Compared to α-Ni(OH)2, α-Ni(OH)2/GO displayed higher chemical reaction rate constants and higher electron transfer rate constants. These differences suggest that the synergy between the α-Ni(OH)2 …