We report on a >100-fold enhancement of Raman responses from Bi2Se3 thin films if laser photon energy switches from 2.33 eV (532 nm) to 1.58 eV (785 nm), which is due to direct optical coupling to Dirac surface states (SS) at the resonance energy of ∼1.5 eV (a thickness-independent enhancement) and due to nonlinearly excited Dirac plasmon (a thickness-dependent enhancement). Owing to the direct optical coupling, we observed an in-plane phonon mode of hexagonally arranged Se-atoms associated with a continuous network of Dirac SS. This mode revealed a Fano lineshape for films <15 nm thick, resulting from quantum interference between surface phonon and Dirac plasmon states.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1088/0953-8984/27/5/052203 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Phonon-Induced Wake Potential in a Graphene-Insulator -Graphene Structure.
Nanomaterials (Basel)
December 2024
Department of Applied Mathematics, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON N2L 3G1, Canada.
The aim of this study is to explore the potential which arises in a graphene-insulator-graphene structure when an external charged particle is moving parallel to it with a speed smaller than the Fermi speed in graphene. This is achieved by employing the dynamic polarization function of graphene within the random phase approximation, where its π electrons are modeled as Dirac fermions, and utilizing a local dielectric function for bulk insulators. Three different insulators are considered: SiO, HfO, and AlO.
View Article and Find Full Text PDFPolarizability, plasmons and damping in pseudospin-1 gapped materials with a flat band.
J Phys Condens Matter
December 2024
Space Vehicles Directorate, US Air Force Research Laboratory, Kirtland Air Force Base, Albuquerque, NM 87117, United States of America.
The subject of our present investigation is the collective electronic properties of various types of pseudospin-1 Dirac-cone materials with a flat band and finite bandgaps in their low-energy spectra. Specifically, we have calculated the dynamical polarization, plasmon dispersions, as well as their decay rates due to Landau damping and presented the closed-form analytical expressions for the wave function overlaps for both the gapped dice lattice and the Lieb lattice. The gapped dice lattice is a special case of the more general-T3model such that its band structure is symmetric and the flat band remains dispersionless.
View Article and Find Full Text PDFOptically driven plasmons in graphene/hBN van der Waals heterostructures: simulating s-SNOM measurements.
Nanophotonics
July 2024
Centre for Advanced Laser Techniques, Institute of Physics, Bijenička 46, 10000 Zagreb, Croatia.
Converting transverse photons into longitudinal two-dimensional plasmon--polaritons (2D-PP) and vice versa presents a significant challenge within the fields of photonics and plasmonics. Therefore, understanding the mechanism which increases the photon - 2D-PP conversion efficiency could significantly contribute to those efforts. In this study, we theoretically examine how efficiently incident radiation, when scattered by a silver spherical nanoparticle (Ag-NP), can be transformed into 2D-PP within van der Waals (vdW) heterostructures composed of hexagonal boron nitride and graphene (hBN/Gr composites).
View Article and Find Full Text PDFPhotonic Dirac waveguide in inhomogeneous spoof surface plasmonic metasurfaces.
Nanophotonics
August 2024
School of Physical Science and Technology & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006, China.
The metamaterial with artificial synthetic gauge field has been proved as an excellent platform to manipulate the transport of the electromagnetic wave. Here we propose an inhomogeneous spoof surface plasmonic metasurface to construct an in-plane pseudo-magnetic field, which is generated by engineering the gradient variation of the opened Dirac cone corresponding to spatially varying mass term. The chiral zeroth-order Landau level is induced by the strong pseudo-magnetic field.
View Article and Find Full Text PDFSpectrally Tunable Ultrafast Long Wave Infrared Detection at Room Temperature.
Nano Lett
November 2024
Department of Physics, University of Central Florida, Orlando, Florida 32816, United States.
Room-temperature longwave infrared (LWIR) detectors are preferred over cryogenically cooled solutions due to the cost effectiveness and ease of operation. The performance of present uncooled LWIR detectors such as microbolometers, is limited by reduced sensitivity, slow response time, and the lack of dynamic spectral tunability. Here, we present a graphene-based efficient room-temperature LWIR detector with high detectivity and fast response time utilizing its tunable optical and electronic characteristics.
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!