scholarly journals Detection of graphene’s divergent orbital diamagnetism at the Dirac point

Science ◽  
2021 ◽  
Vol 374 (6573) ◽  
pp. 1399-1402
Author(s):  
J. Vallejo Bustamante ◽  
N. J. Wu ◽  
C. Fermon ◽  
M. Pannetier-Lecoeur ◽  
T. Wakamura ◽  
...  
Keyword(s):  
Dirac Point

Graphene–polyimide-integrated metasurface for ultrasensitive modulation of higher-order terahertz fano resonances at the Dirac point

2021 ◽  
pp. 150182
Author(s):  
Maosheng Yang ◽  
Tengteng Li ◽  
Ju Gao ◽  
Xin Yan ◽  
Lanju Liang ◽  
...  
Keyword(s):  
Dirac Point ◽  
Higher Order ◽  
Fano Resonances

scholarly journals Discovery of a weak topological insulating state and van Hove singularity in triclinic RhBi2

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Kyungchan Lee ◽  
Gunnar F. Lange ◽  
Lin-Lin Wang ◽  
Brinda Kuthanazhi ◽  
Thaís V. Trevisan ◽  
...  
Keyword(s):  
Time Reversal ◽  
Topological Insulators ◽  
Dirac Point ◽  
Saddle Points ◽  
Surface States ◽  
Van Hove Singularity ◽  
Space Group ◽  
Topological Materials ◽  
Topological Surface ◽  
Optimal Space

AbstractTime reversal symmetric (TRS) invariant topological insulators (TIs) fullfil a paradigmatic role in the field of topological materials, standing at the origin of its development. Apart from TRS protected strong TIs, it was realized early on that more confounding weak topological insulators (WTI) exist. WTIs depend on translational symmetry and exhibit topological surface states only in certain directions making it significantly more difficult to match the experimental success of strong TIs. We here report on the discovery of a WTI state in RhBi2 that belongs to the optimal space group P$$\bar{1}$$ 1 ¯ , which is the only space group where symmetry indicated eigenvalues enumerate all possible invariants due to absence of additional constraining crystalline symmetries. Our ARPES, DFT calculations, and effective model reveal topological surface states with saddle points that are located in the vicinity of a Dirac point resulting in a van Hove singularity (VHS) along the (100) direction close to the Fermi energy (EF). Due to the combination of exotic features, this material offers great potential as a material platform for novel quantum effects.

scholarly journals Emergent flat band electronic structure in a VSe2/Bi2Se3 heterostructure

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Turgut Yilmaz ◽  
Xiao Tong ◽  
Zhongwei Dai ◽  
Jerzy T. Sadowski ◽  
Eike F. Schwier ◽  
...  
Keyword(s):  
Dirac Point ◽  
Electronic States ◽  
Quantum States ◽  
Photoemission Spectroscopy ◽  
Flat Band ◽  
Strongly Correlated ◽  
Dirac Cone ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Topological Materials ◽  
Photoemission Study

AbstractFlat band electronic states are proposed to be a fundamental tool to achieve various quantum states of matter at higher temperatures due to the enhanced electronic correlations. However, materials with such peculiar electronic states are rare and often rely on subtle properties of the band structures. Here, by using angle-resolved photoemission spectroscopy, we show the emergent flat band in a VSe2 / Bi2Se3 heterostructure. Our photoemission study demonstrates that the flat band covers the entire Brillouin zone and exhibits 2D nature with a complex circular dichroism. In addition, the Dirac cone of Bi2Se3 is not reshaped by the flat band even though they overlap in proximity of the Dirac point. These features make this flat band distinguishable from the ones previously found. Thereby, the observation of a flat band in the VSe2 / Bi2Se3 heterostructure opens a promising pathway to realize strongly correlated quantum effects in topological materials.

scholarly journals Dissipative Quantum Hall Effect in Graphene near the Dirac Point

2007 ◽  
Vol 98 (19) ◽  
Author(s):  
Dmitry A. Abanin ◽  
Kostya S. Novoselov ◽  
Uli Zeitler ◽  
Patrick A. Lee ◽  
A. K. Geim ◽  
...  
Keyword(s):  
Hall Effect ◽  
Quantum Hall Effect ◽  
Dirac Point ◽  
Quantum Hall

Trapped photons at a Dirac point: a new horizon for photonic crystals

2014 ◽  
Vol 8 (4) ◽  
pp. 583-589 ◽  
Author(s):  
Kang Xie ◽  
Haiming Jiang ◽  
Allan D. Boardman ◽  
Yong Liu ◽  
Zhenhai Wu ◽  
...  
Keyword(s):  
Photonic Crystals ◽  
Dirac Point

scholarly journals Electrostatic effects, band distortions, and superconductivity in twisted graphene bilayers

2018 ◽  
Vol 115 (52) ◽  
pp. 13174-13179 ◽  
Author(s):  
Francisco Guinea ◽  
Niels R. Walet
Keyword(s):  
Electrostatic Potential ◽  
Small Angle ◽  
Dirac Point ◽  
Unit Cell ◽  
Low Energy ◽  
Energy Bands ◽  
Dependent Change ◽  
Charge Modulation ◽  
Twisted Graphene ◽  
Narrow Bands

Bilayer graphene twisted by a small angle shows a significant charge modulation away from neutrality, as the charge in the narrow bands near the Dirac point is mostly localized in a fraction of the Moiré unit cell. The resulting electrostatic potential leads to a filling-dependent change in the low-energy bands, of a magnitude comparable to or larger than the bandwidth. These modifications can be expressed in terms of new electron–electron interactions, which, when expressed in a local basis, describe electron-assisted hopping terms. These interactions favor superconductivity at certain fillings.

scholarly journals Investigation of quantum transport and local density of states in a graphene strip connected to a square lattice

2021 ◽  
Author(s):  
Elnaz Rostampour
Keyword(s):  
Quantum Transport ◽  
Dirac Point ◽  
Local Density ◽  
Square Lattice ◽  
Density Of State ◽  
Metallic Lead ◽  
Resonant Tunnelling ◽  
Quantum Billiard ◽  
Plasmon Polaritons ◽  
Theoretical Results

Abstract We theoretically express quantum transport at Dirac points via graphene quantum billiard as a non-magnetic material to connect metallic leads. Our results indicate that the quantum billiard of graphene is similar to a resonant tunnelling device. The centerpiece size and the Fermi energy of the graphene quantum billiard play an important role in the resonant tunnelling. In graphene, change of carrier density can affect plasmon polaritons. At the Dirac point, the conductivity of graphene depends on the geometry, so that the conduction of the evanescent modes is close to the theoretical value of 4e2/πh (where Planck's constant and the electron charge are denoted by h and e, respectively.). This transport property can be used to justify chaotic quantum systems and ballistic transistors. Our theoretical results demonstrate that the local density of state of the graphene sheet for EL = ER = 0 is larger than EL = ER = t (where EL (ER) is onsite energy of the left (right) metallic lead) unlike the current obtained from the calculations.

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