AI Article Synopsis
- The study provides direct evidence of broken chirality in graphene by examining electron scattering across various energy levels.
- The researchers successfully measured the energy of the van Hove singularity in the conduction band, aligning well with theoretical models for free-standing graphene.
- They discovered a new intravalley scattering channel that occurs under specific conditions, and the results indicate that higher order electron hopping effects contribute significantly to the breakdown of chirality near the van Hove singularity.
Article Abstract
We present direct experimental evidence of broken chirality in graphene by analyzing electron scattering processes at energies ranging from the linear (Dirac-like) to the strongly trigonally warped region. Furthermore, we are able to measure the energy of the van Hove singularity at the M point of the conduction band. Our data show a very good agreement with theoretical calculations for free-standing graphene. We identify a new intravalley scattering channel activated in case of a strongly trigonally warped constant energy contour, which is not suppressed by chirality. Finally, we compare our experimental findings with T-matrix simulations with and without the presence of a pseudomagnetic field and suggest that higher order electron hopping effects are a key factor in breaking the chirality near to the van Hove singularity.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1103/PhysRevLett.118.116401 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Ballistic Electron Source with Magnetically Controlled Valley Polarization in Bilayer Graphene.
Phys Rev Lett
October 2024
Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands.
The achievement of valley-polarized electron currents is a cornerstone for the realization of valleytronic devices. Here, we report on ballistic coherent transport experiments where two opposite quantum point contacts (QPCs) are defined by electrostatic gating in a bilayer graphene (BLG) channel. By steering the ballistic currents with an out-of-plane magnetic field we observe two current jets, a consequence of valley-dependent trigonal warping.
View Article and Find Full Text PDFProbing the Anisotropic Fermi Surface in Tetralayer Graphene via Transverse Magnetic Focusing.
Nano Lett
May 2024
Department of Physics, Faculty of Science, Chulalongkorn University, Patumwan, Bangkok 10330, Thailand.
Bernal-stacked tetralayer graphene (4LG) exhibits intriguing low-energy properties, featuring two massive sub-bands and showcasing diverse features of topologically distinct, anisotropic Fermi surfaces, including Lifshitz transitions and trigonal warping. Here, we study the influence of the band structure on electron dynamics within 4LG using transverse magnetic focusing. Our analysis reveals two distinct focusing peaks corresponding to the two sub-bands.
View Article and Find Full Text PDFCrystal Symmetry-Dependent In-Plane Hall Effect.
Nano Lett
January 2024
Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore.
The Hall effect has played a vital role in unraveling the intricate properties of electron transport in solid materials. Here, we report on a crystal symmetry-dependent in-plane Hall effect (CIHE) observed in a CuPt/CoPt ferromagnetic heterostructure. Unlike the planar Hall effect (PHE), the CIHE in CuPt/CoPt strongly depends on the current flowing direction (ϕ) with respect to the crystal structure.
View Article and Find Full Text PDFHoneycomb Electron Lattice Induced Dirac Fermion with Trigonal Warping in Bilayer Electrides.
Small
May 2024
State Key Laboratory of Reliability and Intelligence of Electrical Equipment, and School of Materials Science and Engineering, Hebei University of Technology, Tianjin, 300130, China.
Article Synopsis
- This study explores a new type of two-dimensional (2D) Dirac fermions found in electride materials, which are semimetals with unique electron behaviors.
- The newly designed bilayer electride MB (with components Ca/Sr and Cl/Br/I) features excess electrons that create a zigzag honeycomb electron sublattice, shaping distinct Fermi surface properties such as trigonal warping and high anisotropy.
- The electride's structural advantages lead to enhanced electron emission capabilities, paving the way for advanced electronic devices and deeper insights into the relationship between materials and topological states.
Josephson Diode Effect Induced by Valley Polarization in Twisted Bilayer Graphene.
Phys Rev Lett
June 2023
Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
Recently, the Josephson diode effect (JDE), in which the superconducting critical current magnitudes differ when the currents flow in opposite directions, has attracted great interest. In particular, it was demonstrated that gate-defined Josephson junctions based on magic-angle twisted bilayer graphene showed a strong nonreciprocal effect when the weak-link region is gated to a correlated insulating state at half filling (two holes per moiré cell). However, the mechanism behind such a phenomenon is not yet understood.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!