Publications associées à Point groups in three dimensions

Incommensurate phases

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

Diversity of radial spin textures in chiral materials

Oleg Yazyev, Daniel Gosalbez Martinez, Alberto Crepaldi

We introduce a classification of the radial spin textures in momentum space that emerge at the high-symmetry points in crystals characterized by nonpolar chiral point groups (D2, D3, D4, D6, T, O). Based on the symmetry constraints imposed by these point g ...

Amer Physical Soc2023

Duality and bicrystals on infinite binary matrices

Thomas Gerber

The set of finite binary matrices of a given size is known to carry a finite type AA bicrystal structure. We first review this classical construction, explain how it yields a short proof of the equality between Kostka polynomials and one-dimensional sums t ...

2023

Periodic and Aperiodic NiFe Nanomagnet/Ferrimagnet Hybrid Structures for 2D Magnon Steering and Interferometry with High Extinction Ratio

Dirk Grundler, Sho Watanabe, Andrea Mucchietto, Shixuan Shan, Elif Nur Dayi, Vinayak Shantaram Bhat

Magnons, quanta of spin waves, are known to enable information processing with low power consumption at the nanoscale. So far, however, experimentally realized half-adders, wave-logic and binary output operations were based on few µm-long spin waves and re ...

Wiley2023

Shear and Breathing Modes of Layered Materials

Nicola Marzari, Giovanni Pizzi, Marco Gibertini

Layered materials (LMs), such as graphite, hexagonal boron nitride, and transition-metal dichalcogenides, are at the center of an ever-increasing research effort, due to their scientific and technological relevance. Raman and infrared spectroscopies are ac ...

AMER CHEMICAL SOC2021

Promoting Persistent Superionic Conductivity in Sodium Monocarba-closo-dodecaborate NaCB11H12 via Confinement within Nanoporous Silica

Mirjana Dimitrievska

Superionic phases of bulk anhydrous salts based on large cluster-like polyhedral (carba)borate anions are generally stable only well above room temperature, rendering them unsuitable as solid-state electrolytes in energy-storage devices that typically oper ...

AMER CHEMICAL SOC2021

Quantum spin liquid phases in the bilinear-biquadratic two-SU(4)-fermion Hamiltonian on the square lattice

Olivier Clément Romain Gauthé

We consider the phase diagram of the most general SU(4)-symmetric two-site Hamiltonian for a system of two fermions per site (i.e., self-conjugate 6 representation) on the square lattice. It is known that this model hosts magnetic phases breaking SU(4) sym ...

AMER PHYSICAL SOC2020

Non-Abelian reciprocal braiding of Weyl points and its manifestation in ZrTe

Oleg Yazyev, Quansheng Wu

Weyl points in three-dimensional systems with certain symmetry carry non-Abelian topological charges, which can be transformed via non-trivial phase factors that arise upon braiding these points inside the reciprocal space. ...

NATURE PUBLISHING GROUP2020

New refinement of the crystal structure of Zn(NH3)(2)Cl-2 at 100 K

Arnaud Magrez, Trpimir Ivsic

The crystal structure of [ZnCl2(NH3)(2)], diamminedichloridozinc, was reinvestigated at low temperature, revealing the positions of the hydrogen atoms and thus a deeper insight into the hydrogen-bonding scheme in the crystal packing. In comparison with pre ...

2019

Efficient Multi-dimensional Diracs Estimation with Linear Sample Complexity

Martin Vetterli, Thierry Blu, Hanjie Pan

Estimating Diracs in continuous two or higher dimensions is a fundamental problem in imaging. Previous approaches extended one dimensional methods, like the ones based on finite rate of innovation (FRI) sampling, in a separable manner, e.g., along the hori ...

2018

Patching And Weak Approximation In Isometry Groups

Eva Bayer Fluckiger

Let R be a semilocal principal ideal domain. Two algebraic objects over R in which scalar extension makes sense (e.g. quadratic spaces) are said to be of the same genus if they become isomorphic after extending scalars to all completions of R and its fract ...

Amer Mathematical Soc2017

Shapes from pixels

Martin Vetterli, Loïc Arnaud Baboulaz, Arash Amini, Mitra Fatemi

Continuous-domain visual signals are usually captured as discrete (digital) images. This operation is not invertible in general, in the sense that the continuous-domain signal cannot be exactly reconstructed based on the discrete image, unless it satisfies ...

Institute of Electrical and Electronics Engineers2016

Unsplittable Coverings in the Plane

János Pach, Doemoetoer Palvoelgyi

A system of sets forms an m-fold covering of a set X if every point of X belongs to at least m of its members. A 1-fold covering is called a covering. The problem of splitting multiple coverings into several coverings was motivated by classical density est ...

Springer-Verlag Berlin2016

Unsplittable coverings in the plane

János Pach, Doemoetoer Palvoelgyi

A system of sets forms an m-fold covering of a set X if every point of X belongs to at least m of its members. A 1-fold covering is called a covering. The problem of splitting multiple coverings into several coverings was motivated by classical density est ...

Academic Press Inc Elsevier Science2016

Spectral signatures of high-symmetry quantum dots and effects of symmetry breaking

Elyahou Kapon, Alok Rudra, Marc-André Dupertuis, Daniel Oberli, Valentina Troncale

High symmetry epitaxial quantum dots (QDs) with three or more symmetry planes provide a very promising route for the generation of entangled photons for quantum information applications. The great challenge to fabricate nanoscopic high symmetry QDs is furt ...

Iop Publishing Ltd2015

High pressure induced spin state crossover in Sr2CaYCo4O10.5

Jonathan White

The layered cobaltite Sr2CaYCo4O10.5 with formal average cobalt oxidation state close to 3+ has been studied as functions of both temperature and pressure up to 4GPa by neutron powder diffraction (NPD). The crystal structure is shown to have tetragonal sym ...

Institute of Physics2015

An indiscrete Bieberbach theorem: from amenable CAT$(0)$ groups to Tits buildings

Nicolas Monod

Non-positively curved spaces admitting a cocompact isometric action of an amenable group are investigated. A classification is established under the assumption that there is no global fixed point at infinity under the full isometry group. The visual bounda ...

2015

Icosahedral quasicrystal-enhanced nucleation of the fcc phase in liquid gold alloys

Michel Rappaz, Güven Kurtuldu, Alberto Sicco

Although the grain refinement of yellow gold alloys with Jr has been used in industry and known for nearly half a century, the basic mechanism is still unknown. The present contribution shows that the mechanism is the same as that evidenced recently in Al- ...

Elsevier2014

Infinite Presentability Of Groups And Condensation

Luc Guyot

We describe various classes of infinitely presented groups that are condensation points in the space of marked groups. A well-known class of such groups consists of finitely generated groups admitting an infinite minimal presentation. We introduce here a l ...

Cambridge University Press2014

L4Fe2As2Te1-xO4-yFy (L = Pr, Sm, Gd): A layered oxypnictide superconductor with T-c up to 45 K

László Forró, Richard Gaal, Janusz Andrzej Karpinski, Andrea Pisoni, Sergiy Katrych

The synthesis and structural and physical properties of iron lanthanide oxypnictide superconductors, L4Fe2As2Te1-xO4 (L = Pr, Sm, Gd), with transition temperature at similar to 25 K are reported. Single crystals have been grown at high pressure using the c ...

Amer Physical Soc2014