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A spectrally formulated finite element analysis based methodology has been proposed to calculate phononic band structure of reticulated honeycomb lattices having translationally invariant repetitive elements called unit cells. Bloch…

Materials Science · Physics 2015-09-30 Sushovan Mukherjee , S. Gopalakrishnan

Engineering of phonons, i.e., collective lattice vibrations in crystals, is essential for manipulating physical properties of materials such as thermal transport, electron-phonon interaction, confinement of lattice vibration, and optical…

Materials Science · Physics 2022-02-04 Seung Gyo Jeong , Ambrose Seo , Woo Seok Choi

We consider two-dimensional phononic crystals formed from silicon and voids, and present optimized unit cell designs for (1) out-of-plane, (2) in-plane and (3) combined out-of-plane and in-plane elastic wave propagation. To feasibly search…

Computational Physics · Physics 2013-04-23 Osama R. Bilal , Mahmoud I. Hussein

We suggest and implement a parallelization scheme based on an efficient multiband eigenvalue solver, called the locally optimal block preconditioned conjugate gradient LOBPCG method, and using an optimized three-dimensional (3D) fast…

Materials Science · Physics 2010-06-02 François Bottin , Stéphane Leroux , Andrew Knyazev , Gilles Zérah

Beyond classical Bragg diffraction, we report on new sub-Bragg phenomena to achieve enhanced sound wave tunability in the low-frequency range in a multilayered acoustic metamaterial system. Remarkably, we reveal and study the formation of…

Applied Physics · Physics 2024-10-03 Majdi O. Gzal , Lawrence A. Bergman , Kathryn H. Matlack , Alexander F. Vakakis

Relying on the anharmonic special displacement method, we introduce an ab initio quasistatic polymorphous framework to describe local disorder, anharmonicity, and electron-phonon coupling in superionic conductors. Using the example of cubic…

Flax fibres are valuable reinforcements for tomorrow's composites. However, defects called kink-bands, which mainly appear on fibres during the extraction and transformation phases, might affect their mechanical properties. Defects induced…

Systematic and automatic calculations of the electronic band structure are a crucial component of computationally-driven high-throughput materials screening. An algorithm, for any crystal, to derive a unique description of the crystal…

Materials Science · Physics 2023-04-24 Yoyo Hinuma , Giovanni Pizzi , Yu Kumagai , Fumiyasu Oba , Isao Tanaka

Here we apply hyperspectral bright field imaging to collect computed tomographic images with excellent energy resolution (800 eV), applying it for the first time to map the distribution of stain in a fixed biological sample through its…

A finite element method (FEM) for solving the complex valued k({\omega}) vs. {\omega} dispersion curve of a 3D metamaterial/photonic crystal system is presented. This 3D method is a generalization of a previously reported 2D eigenvalue…

Materials Science · Physics 2015-05-28 Chris Fietz , Yaroslav Urzhumov , Gennady Shvets

This paper presents an innovative approach to computational acoustic imaging of biperiodic surfaces, exploiting the capabilities of an acoustic superlens to overcome the diffraction limit. We address the challenge of imaging physical…

Analysis of PDEs · Mathematics 2026-01-05 Yuliang Wang

Recent research in materials science opens exciting perspectives to design novel quantum materials and devices, but it calls for quantitative predictions of properties which are not accessible in standard first principles packages. PAOFLOW…

Using a computationally inexpensive frozen phonon approach we have developed a technique which can be used to screen large unit cell materials and systems for enhanced superconducting critical temperatures. The method requires only density…

Superconductivity · Physics 2024-05-07 Oliver A. Dicks , Kateryna Foyevtsova , Ilya Elfimov , Rohit Prasankumar , George Sawatzky

Medical ultrasound provides images which are the spatial map of the tissue echogenicity. Unfortunately, an ultrasound image is a low-quality version of the expected Tissue Reflectivity Function (TRF) mainly due to the non-ideal Point Spread…

Image and Video Processing · Electrical Eng. & Systems 2021-09-28 Sobhan Goudarzi , Hassan Rivaz

Solid-state elastic-wave phonons are a promising platform for a wide range of quantum information applications. An outstanding challenge and enabling capability in harnessing phonons for quantum information processing is achieving strong…

Applied Physics · Physics 2024-05-07 Eric Chatterjee , Alexander Wendt , Daniel Soh , Matt Eichenfield

In this work, the Effective Phonon Dispersion of $\beta$- (Al$_x$Ga$_{1-x}$)$_2$O$_3$ alloy is investigated using the Phonon unfolding formalism. To capture the true randomness of the system, supercells are designed using the technique of…

Materials Science · Physics 2023-12-29 Ankit Sharma , Animesh Datta , Uttam Singisetti

Phononic crystals and metamaterials take advantage of pre-designed geometrical structures to sculpt elastic waves, controlling their dispersion using different mechanisms. These mechanisms revolve mostly around Bragg scattering (BS), local…

Applied Physics · Physics 2018-05-23 André Foehr , Osama R. Bilal , Sebastian D. Huber , Chiara Daraio

Instrumental aberrations strongly limit high-contrast imaging of exoplanets, especially when they produce quasistatic speckles in the science images. With the help of recent advances in deep learning, we have developed in previous works an…

Instrumentation and Methods for Astrophysics · Physics 2022-11-14 Maxime Quesnel , Gilles Orban de Xivry , Olivier Absil , Gilles Louppe

We perform the scanning tunneling spectroscopy based superconductor-vacuum-superconductor analogue to the seminal McMillan and Rowell superconductor-insulator-superconductor device study of phonons in the archetypal elemental superconductor…

Superconductivity · Physics 2012-11-13 F. C. Niestemski , S. Johnston , A. W. Contryman , C. D. Camp , T. P. Devereaux , H. C. Manoharan

A method to analyze optical transitions is developed by combining the Kubo-Greenwood formula with the unfolding method to construct an unfolded electronic band structure with optical transition weights, which allows us to investigate how…

Materials Science · Physics 2020-08-31 Yung-Ting Lee , Chi-Cheng Lee , Masahiro Fukuda , Taisuke Ozaki