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Concept

Quasi-cristal

Publications associées (29)

Incommensurate phases

Gervais Chapuis

Incommensurately modulated crystalline phases are part of a more general family called aperiodic crystals. Their symmetry is treated within the theoretical framework of superspace groups that is a generalization of the 3D space groups that are used for con ...

Academic Press2024

Spin dynamics, loop formation and cooperative reversal in artificial quasicrystals with tailored exchange coupling

Dirk Grundler, Sho Watanabe, Vinayak Shantaram Bhat

Aperiodicity and un-conventional rotational symmetries allow quasicrystalline structures to exhibit unusual physical and functional properties. In magnetism, artificial ferromagnetic quasicrystals exhibited knee anomalies suggesting reprogrammable magnetic ...

2023

What do we talk about, when we talk about single-crystal termination-dependent selectivity of Cu electrocatalysts for CO2 reduction? A data-driven retrospective

Kevin Rossi

We mine from the literature experimental data on the CO2 electrochemical reduction selectivity of Cu single crystal surfaces. We then probe the accuracy of a machine learning model trained to predict faradaic efficiencies for 11 CO2 reduction reaction prod ...

ROYAL SOC CHEMISTRY2023

Pressure-freezing of dodecane: exploring the crystal structures, formation kinetics and phase diagrams for colossal barocaloric effects in n-alkanes

Tomasz Poreba

Barocaloric (BC) materials provide cheaper and more energy efficient alternatives to traditional refrigerants. Some liquid alkanes were recently shown to exhibit a colossal BC effect, matching the entropy changes in commercial vapour-liquid refrigerants. D ...

Royal Soc Chemistry2023

Influence of Sphericity on Surface Termination of Icosahedral Colloidal Clusters

Esther Amstad

Colloids self-organize into icosahedral clusters composed of a Mackay core and an anti-Mackay shell under spherical confinement to minimize the free energy. This study explores the variation of surface arrangements of colloids in icosahedral clusters, focu ...

Wiley-V C H Verlag Gmbh2023

Machine learning for metallurgy IV: A neural network potential for Al-Cu-Mg and Al-Cu-Mg-Zn

William Curtin, Daniel John Gilles Marchand

Most metallurgical properties, e.g., dislocation propagation, precipitate formation, can only be fully understood atomistically but most phenomena and quantities of interest cannot be measured experimentally. Accurate simulation methods are essential but f ...

2022

Magnons, worms and nanogratings in artificial magnetic quasicrystals

Sho Watanabe

Magnons (spin waves, SWs) are elementary spin excitations in magnetically ordered materials. They are the promising quanta for the transmission and processing of information. Magnons can be coupled to the electromagnetic waves utilized for the wireless com ...

EPFL2021

Direct observation of multiband transport in magnonic Penrose quasicrystals via broadband and phase-resolved spectroscopy

Dirk Grundler, Mohammad Hamdi, Korbinian Baumgärtl, Sho Watanabe, Vinayak Shantaram Bhat

Quasicrystals are aperiodically ordered structures with unconventional rotational symmetry. Their peculiar features have been explored in photonics to engineer bandgaps for light waves. Magnons (spin waves) are collective spin excitations in magnetically o ...

2021

Theory-Guided Enhancement of CO2 Reduction to Ethanol on Ag-Cu Tandem Catalysts via Particle-Size Effects

Raffaella Buonsanti, Pranit Srinivas Iyengar, James Richard Pankhurst

In the CO2 reduction reaction, the design of electrocatalysts that selectively promote alcohols over hydrocarbons (e.g., ethanol over ethylene) hinges on the understanding of the pathways and specific sites that form alcohols. Herein, theoretical considera ...

2021

Crystallization kinetics of atomic crystals revealed by a single-shot and single-particle X-ray diffraction experiment

Christoph Bostedt

Crystallization is a fundamental natural phenomenon and the ubiquitous physical process in materials science for the design of new materials. So far, experimental observations of the structural dynamics in crystallization have been mostly restricted to slo ...

National Academy of Sciences2021

Preferential out-of-plane conduction and quasi-one-dimensional electronic states in layered 1T-TaS2

Helmuth Berger, László Forró, Alla Arakcheeva, Ana Akrap, Philip Johannes Walter Moll, Matthias Carsten Putzke, Edoardo Martino, Andrea Pisoni, Luka Ciric, Konstantin Semeniuk

Layered transition metal dichalcogenides (TMDs) are commonly classified as quasi-two-dimensional materials, meaning that their electronic structure closely resembles that of an individual layer, which results in resistivity anisotropies reaching thousands. ...

2020

Influence of Minor Cr Additions on Crystal Growth in Rapidly Solidified Al-20Zn Alloys

Michel Rappaz

It has been discovered quite recently that Icosahedral Short-Range Order (ISRO) of atoms in the liquid phase of metallic alloys surrounding some trace elements added to the melt can influence both the nucleation and growth of the primary phase. In this wor ...

2020

Direct Observation of Worm‐Like Nanochannels and Emergent Magnon Motifs in Artificial Ferromagnetic Quasicrystals

Dirk Grundler, Sho Watanabe, Vinayak Shantaram Bhat

Quasicrystalline structures and aperiodic metamaterials find applications ranging from established consumer gadgets to potential high‐tech photonic components owing to both complex arrangements of constituents and exotic rotational symmetries. Magnonics is ...

2020

Solid-state to solution helicity inversion of pseudotetrahedral chiral copper(II) complexes with 2,4-dihalo-salicylaldiminate ligands

Rosario Scopelliti

The enantiopure Schiff bases (R or S)-N-1-( phenyl)ethyl-2,4-X-1,X2(-)salicylaldimine (X-1, X-2 = Cl, Br, I) coordinate to copper(II) and provide pseudotetrahedral bis[(S or R)-N-1-(phenyl)ethyl-(2,4-X-1,X-2-salicylaldiminato.2N,O)]-./.-Cu(II) (kappa N-2,O ...

ROYAL SOC CHEMISTRY2020

Progress in modelling solidification microstructures in metals and alloys. Part II: dendrites from 2001 to 2018

Michel Rappaz, Wilfried Kurz

This is the first account of the history of modelling dendritic and cellular solidification. While Part I reviewed the progress up to the year 2000 [Kurz W, Fisher DJ, Trivedi R. Progress in modelling solidification microstructures in metals and alloys: de ...

TAYLOR & FRANCIS LTD2021

Solidification of Metallic Alloys: Does the Structure of the Liquid Matter?

Michel Rappaz, Güven Kurtuldu

In 1952, Frank (Proc R Soc Lond Ser-Math Phys Sci 215:43-46, 1952) already postulated that Icosahedral Short Range Order (ISRO) of atoms in the liquid could possibly explain the large nucleation undercoolings measured in metallic alloys by Turnbull and Fis ...

SPRINGER2020

Chalcogenide glasses for innovation in applied science: fundamental issues and new insights

Assil Bouzid

We provide an overview of what has been accomplished by our team, since 1998, in the area of first-principles molecular dynamics (FPMD) modeling of glassy chalcogenides, a prototypical family of network-forming disordered materials. After a broad introduct ...

IOP PUBLISHING LTD2020

Grain morphology reconstruction of crystalline materials from Laue three-dimensional neutron diffraction tomography

Marina Garcia Gonzalez

The macroscopic properties of advanced engineering and functional materials are highly dependent on their overall grain orientation distribution, size, and morphology. Here we present Laue 3D neutron diffraction tomography providing reconstructions of the ...

Nature Research2020

The emergence of small-scale self-affine surface roughness from deformation

Till Junge

Most natural and man-made surfaces appear to be rough on many length scales. There is presently no unifying theory of the origin of roughness or the self-affine nature of surface topography. One likely contributor to the formation of roughness is deformati ...

AMER ASSOC ADVANCEMENT SCIENCE2020

Influence of Ir Additions and Icosahedral Short Range Order (ISRO) on Nucleation and Growth Kinetics in Au-20.5Wt Pct Cu-4.5Wt PctAg Alloy

Michel Rappaz

Based on detailed EBSD analyses, Kurtuldu et al. (Acta Mater. 70:240-248, 2014) have explained the grain refinement of Au-12.5 wt pctCu-12.5 wt pctAg (yellow gold) by the addition of minute amounts of Ir in terms of icosahedral quasicrystal (iQC)-mediated ...

SPRINGER2019