Quantum oscillations are generally studied to resolve the electronic structure of topological insulators. In Cu(0.25)Bi(2)Se(3), the prime candidate of topological superconductors, quantum oscillations are still not observed in magnetotransport measurement. However, using torque magnetometry, quantum oscillations (the de Haas-van Alphen effect) were observed in Cu(0.25)Bi(2)Se(3). The doping of Cu in Bi(2)Se(3) increases the carrier density and the effective mass without increasing the scattering rate or decreasing the mean free path. In addition, the Fermi velocity remains the same in Cu(0.25)Bi(2)Se(3) as that in Bi(2)Se(3). Our results imply that the insertion of Cu does not change the band structure and that conduction electrons in Cu doped Bi(2)Se(3) sit in the linear Dirac-like band.
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http://dx.doi.org/10.1103/PhysRevLett.109.226406 | DOI Listing |
The extreme electromagnetic near-field environment of nanoplasmonic resonators and metamaterials can give rise to unprecedented electromagnetic heating effects, enabling large and manipulable temperature gradients on the order of 10-10 K/nm. In this Letter, by interfacing traditional semiconductor quantum dots with industry-grade plasmonic transducer technology, we demonstrate that the near-field-induced thermal gradient can facilitate the requisite population inversion for coherent phonon amplification and lasing at the nanoscale. Our detailed analysis uncovers both the characteristics and parameter sensitivity of inversion and relaxation oscillations in the system, thereby unveiling hitherto unexplored opportunities for leveraging plasmonic near-field effects in the context of quantum thermodynamics and phononics.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Terahertz Research Center, School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China.
Low-dimensional materials (LDMs) with unique electromagnetic properties and diverse local phenomena have garnered significant interest, particularly for their low-energy responses within the terahertz (THz) range. Achieving deep subwavelength resolution, THz nanoscopy offers a promising route to investigate LDMs at the nanoscale. Steady-state THz nanoscopy has been demonstrated as a powerful tool for investigating light-matter interactions across boundaries and interfaces, enabling insights into physical phenomena such as localized collective oscillations, quantum confinement of quasiparticles, and metal-to-insulator phase transitions (MITs).
View Article and Find Full Text PDFJ Org Chem
January 2025
Division of Theoretical Chemistry, IFM, Linköping University, 58183 Linköping, Sweden.
The harmonic oscillator model of aromaticity (HOMA) offers a straightforward route to quantifying aromaticity that requires no other information than the bond lengths of the conjugated ring in question. Given that such information is often readily obtainable from quantum-chemical calculations, it is pertinent to improve this parametrized model as much as possible. Here, a new version of HOMA is presented where, atypically, the corresponding parameters are derived from the actual bond lengths of both aromatic and antiaromatic (rather than nonaromatic) reference compounds, as calculated with a high-level method.
View Article and Find Full Text PDFMolecules
December 2024
Department of Physical and Quantum Chemistry, Wrocław University of Science and Technology, 50-370 Wrocław, Poland.
We report the results of calculations of the linear polarizability and second hyperpolarizability of the H molecule in the bond dissociation process. These calculations were performed for isolated molecules, as well as molecules under spatial confinement. The spatial confinement was modeled using the external two-dimensional (cylindrical) harmonic oscillator potential.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
Faculty of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan.
In this study, the radiative and nonradiative decay pathways from the first singlet excited states (denoted as S) of three bithiophene-fused isoquinolines were investigated by using the mixed-reference spin-flip time-dependent density functional theory approach. These isoquinolines, which are prepared via [2 + 2 + 2] cycloaddition reactions between three types of bithiophene-linked diynes and nitriles, exhibit different fluorescence quantum yields in response to the positions of their sulfur atoms. The decay processes, including the fluorescence emission and internal conversion, were considered.
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