Concept

Groupe ponctuel de symétrie

Publications associées (23)

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 ...

College Pk2023

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

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

ASTErIsM: application of topometric clustering algorithms in automatic galaxy detection and classification

Jean-Paul Richard Kneib, Frédéric Courbin, Danuta Janina Paraficz

We present a study on galaxy detection and shape classification using topometric clustering algorithms. We first use the DBSCAN algorithm to extract, from CCD frames, groups of adjacent pixels with significant fluxes and we then apply the DENCLUE algorithm ...

Oxford Univ Press2016

La coupe du roi and other methods to halve objects

Dieter Schwarzenbach

The symmetry theory of halving objects into two identical fragments is developed and illustrated by examples. La coupe du roi is a fascinating way to slice an apple into chiral fragments with the same handedness. It may be applied to any object with point ...

De Gruyter2015

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

Analysing Friedel averages and differences

Philip Pattison

Various practical applications of the average (A) and difference (D) of Friedel opposites are described. Techniques based on the resonant-scattering contribution to Friedel differences are applied to see whether a crystal is centrosymmetric or not, and to ...

Wiley-Blackwell2012

Closing Large Hyperbolic 2g-gons

Poincaré's uniformisation theorem says that any Riemann surface is conformally equivalent to a unique (up to isometry) surface of constant Gauss curvature 0, 1 or –1. The (topologically) richest of these three worlds is for curvature –1 formed of hyperboli ...

EPFL2012

Intertwining of Zeeman and Coulomb interactions on excitons in highly symmetric semiconductor quantum dots

Daniel Oberli

We present an experimental study and develop a group theoretical analysis of the Zeeman effect on excitons in pyramidal semiconductor quantum dots possessing the symmetries of the C3v point group. The magnetic field dependence of the emission pattern origi ...

2012

Obtaining molecular orientation from second harmonic and sum frequency scattering experiments in water: angular distribution and polarization dependence

Sylvie Roke

We present a method for determining molecular orientation from second-order nonlinear light scattering experiments. Our modeling shows that there is an optimal angular region, for which the scattering pattern is most sensitive to molecular orientation. We ...

2010

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