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Full-Text Articles in Physical Sciences and Mathematics
Strong Electron-Boson Coupling In The Iron-Based Superconductor Bafe1.9pt0.1as2 Revealed By Infrared Spectroscopy, Zhen Xing, Shanta Saha, J. Paglione, M. M. Qazilbash
Strong Electron-Boson Coupling In The Iron-Based Superconductor Bafe1.9pt0.1as2 Revealed By Infrared Spectroscopy, Zhen Xing, Shanta Saha, J. Paglione, M. M. Qazilbash
Arts & Sciences Articles
Understanding the formation of Cooper pairs in iron-based superconductors is one of the most important topics in condensed matter physics. In conventional superconductors, the electron-phonon interaction leads to the formation of Cooper pairs. In conventional strong-coupling superconductors like lead (Pb), the features due to electron-phonon interaction are evident in the infrared absorption spectra. Here we investigate the infrared absorption spectra of the iron arsenide superconductor BaFe1.9Pt0.1As2. We find that this superconductor has fully gapped (nodeless) Fermi surfaces, and we observe the strong-coupling electron-boson interaction features in the infrared absorption spectra. Through modeling with the Eliashberg function based on Eliashberg theory, …
Highly Repeatable Nanoscale Phase Coexistence In Vanadium Dioxide Films, T. J. Huffman, D. J. Lahneman, (...), M. M. Qazilbash
Highly Repeatable Nanoscale Phase Coexistence In Vanadium Dioxide Films, T. J. Huffman, D. J. Lahneman, (...), M. M. Qazilbash
Arts & Sciences Articles
It is generally believed that in first-order phase transitions in materials with imperfections, the formation of phase domains must be affected to some extent by stochastic (probabilistic) processes. The stochasticity would lead to unreliable performance in nanoscale devices that have the potential to exploit the transformation of physical properties in a phase transition. Here we show that stochasticity at nanometer length scales is completely suppressed in the thermally driven metal-insulator transition (MIT) in sputtered vanadium dioxide (VO2) films. The nucleation and growth of domain patterns of metallic and insulating phases occur in a strikingly reproducible way. The completely deterministic nature …
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).
Ultra-Thin Perfect Absorber Employing A Tunable Phase Change Material, Mikhail A. Kats, Deepika Sharma, (...), M. M. Qazilbash, Et Al.
Ultra-Thin Perfect Absorber Employing A Tunable Phase Change Material, Mikhail A. Kats, Deepika Sharma, (...), M. M. Qazilbash, Et Al.
Arts & Sciences Articles
We show that perfect absorption can be achieved in a system comprising a single lossy dielectric layer of thickness much smaller than the incident wavelength on an opaque substrate by utilizing the nontrivial phase shifts at interfaces between lossy media. This design is implemented with an ultra-thin (∼λ/65) vanadium dioxide (VO2) layer on sapphire, temperature tuned in the vicinity of the VO2 insulator-to-metal phase transition, leading to 99.75% absorption at λ = 11.6 μm. The structural simplicity and large tuning range (from ∼80% to 0.25% in reflectivity) are promising for thermal emitters, modulators, and bolometers.
Insulator-To-Metal Transition And Correlated Metallic State Of V 2 O 3 Investigated By Optical Spectroscopy, M. K. Stewart, D. Brownstead, (...), M. M. Qazilbash, Et Al.
Insulator-To-Metal Transition And Correlated Metallic State Of V 2 O 3 Investigated By Optical Spectroscopy, M. K. Stewart, D. Brownstead, (...), M. M. Qazilbash, Et Al.
Arts & Sciences Articles
The optical properties of V2O3 thin films are investigated across the insulator-to-metal transition and in the metallic state. The spectral weight transfer observed across the transition, over an energy scale of 5 eV, is consistent with the Mott-Hubbard model for correlated electron systems. In the metallic phase, a strong Drude peak is observed, which exhibits a pronounced temperature dependence related to the transfer of states from the Hubbard bands to the quasiparticle peaks as the temperature is reduced. The analysis of the far-infrared spectra reveals signatures of strong electronic correlations in V2O3. Finally, a comparison to VO2 data is presented.