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Full-Text Articles in Physics
Spatial Interferences Of Photodetachment Near A Repulsive Center, B. C. Yang, John B. Delos, M. L. Du
Spatial Interferences Of Photodetachment Near A Repulsive Center, B. C. Yang, John B. Delos, M. L. Du
Arts & Sciences Articles
We study the detached-electron flux distributions from the photodetachment of electrons from a negative ion near a repulsive center. Using a semiclassical approach, we calculate the electron flux on spherical detectors with various radii. The classically allowed angular range of the interference patterns on the spherical screen increases as the detached-electron energy is increased. In the classically allowed range, we find that there are always two trajectories going from the negative ion to the observation point on the screen, inducing quantum interference patterns. We have also extended the formulas into the tunneling region. The interference patterns also reflect the quantum …
Anisotropic Infrared Response Of Vanadium Dioxide Microcrystals, T. J. Huffman, Peng Xu, M. M. Qazilbash, Et Al.
Anisotropic Infrared Response Of Vanadium Dioxide Microcrystals, T. J. Huffman, Peng Xu, M. M. Qazilbash, Et Al.
Arts & Sciences Articles
Vanadium dioxide (VO2) undergoes a phase transition at a temperature of 340 K between an insulating monoclinic M-1 phase and a conducting rutile phase. Accurate measurements of possible anisotropy of the electronic properties and phonon features of VO2 in the insulating monoclinic M-1 and metallic rutile phases are a prerequisite for understanding the phase transition in this correlated system. Recently, it has become possible to grow single domain untwinned VO2 microcrystals, which makes it possible to investigate the true anisotropy of VO2. We performed polarized transmission infrared micro-spectroscopy on these untwinned microcrystals in the spectral range between 200 cm(-1) and …
Thermal Tuning Of Mid-Infrared Plasmonic Antenna Arrays Using A Phase Change Material, Mikhail A. Kats, Romain Blanchard, (...), M. M. Qazilbash, Et Al.
Thermal Tuning Of Mid-Infrared Plasmonic Antenna Arrays Using A Phase Change Material, Mikhail A. Kats, Romain Blanchard, (...), M. M. Qazilbash, Et Al.
Arts & Sciences Articles
We demonstrate that the resonances of infrared plasmonic antennas can be tuned or switched on/off by taking advantage of the thermally driven insulator-to-metal phase transition in vanadium dioxide (VO2). Y-shaped antennas were fabricated on a 180 nm film of VO2 deposited on a sapphire substrate, and their resonances were shown to depend on the temperature of the VO2 film in proximity of its phase transition, in good agreement with full-wave simulations. We achieved tunability of the resonance wavelength of approximately 10% (>1 μm at λ ∼ 10 μm).
Model Sensitivity In Holographic Superconductors And Their Deconstructed Cousins, Joshua X. Erlich, Zhen Wang
Model Sensitivity In Holographic Superconductors And Their Deconstructed Cousins, Joshua X. Erlich, Zhen Wang
Arts & Sciences Articles
Holographic models of superconductors successfully reproduce certain experimental features of high-temperature superconductors, such as a large gap-to-Tc ratio compared to that of conventional superconductors. By deconstructing the extra dimension of these holographic models, similar phenomenology is described by a class of models defined in the natural dimension of the superconducting system. We analyze the sensitivity of certain observables in holographic and deconstructed holographic superconductors to details of the extra-dimensional spacetime. Our results support the notion that certain quantitative successes of simple models of this type are accidental. However, we also find a certain universal relationship between superconducting observables.
Excited State Calculations In Solids By Auxiliary-Field Quantum Monte Carlo, Fengjie Ma, Shiwei Zhang, Henry Krakauer
Excited State Calculations In Solids By Auxiliary-Field Quantum Monte Carlo, Fengjie Ma, Shiwei Zhang, Henry Krakauer
Arts & Sciences Articles
We present an approach for ab initio many-body calculations of excited states in solids. Using auxiliary-field quantum Monte Carlo, we introduce an orthogonalization constraint with virtual orbitals to prevent collapse of the stochastic Slater determinants in the imaginary-time propagation. Trial wave functions from density-functional calculations are used for the constraints. Detailed band structures can be calculated. Results for standard semiconductors are in good agreement with experiments; comparisons are also made with GW calculations and the connections and differences are discussed. For the challenging ZnO wurtzite structure, we obtain a fundamental band gap of 3.26(16) eV, consistent with experiments.