Publications associées à Symétrie centrale

Band Gap Renormalization at Different Symmetry Points in Perovskites

Using ultrafast broad-band transient absorption (TA) spectroscopy of photoexcited MAPbBr3 thin films with probe continua in the visible and the mid- to deep-ultraviolet (UV) ranges, we capture the ultrafast renormalization at the fundamental gap at the R s ...

Amer Chemical Soc2024

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

Induced giant piezoelectricity in centrosymmetric oxides

Paul Muralt, Dragan Damjanovic, Mahmoud Hadad, Vasiliki Tileli, Lukas Riemer, Daesung Park

Piezoelectrics are materials that linearly deform in response to an applied electric field. As a fundamental prerequisite, piezoelectric materials must have a noncentrosymmetric crystal structure. For more than a century, this has remained a major obstacle ...

American Association for the Advancement of Science2022

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

Emergence of Nontrivial Low-Energy Dirac Fermions in Antiferromagnetic EuCd2As2

Joël Mesot, Vladimir N. Strocov, Pierre Richard, Han Wang, Hang Li

Parity-time symmetry plays an essential role for the formation of Dirac states in Dirac semimetals. So far, all of the experimentally identified topologically nontrivial Dirac semimetals (DSMs) possess both parity and time reversal symmetry. The realizatio ...

Wiley-V C H Verlag Gmbh2020

Reflection for action: designing tools to support teacher reflection on everyday evidence

Pierre Dillenbourg

Improving educational practice through reflection is one important focus of teacher professional development approaches. However, such teacher reflection operates under practical classroom constraints that make it happen infrequently, including the relianc ...

ROUTLEDGE JOURNALS, TAYLOR & FRANCIS LTD2020

Modeling of TAE mode excitation with an antenna in realistic X-point geometry

Ambrogio Fasoli, Duccio Testa

Experimentally, it is observed that Toroidal Alfven Eigenmodes (TAEs) are difficult to excite with an external antenna when the plasma is in X-point geometry. Here, the effect of the X-point geometry on the efficiency of the TAE excitation with the externa ...

AMER INST PHYSICS2020

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

On design strategies for binary dielectric metasurfaces based on the Fourier modal method

Kévin Müller

Binary dielectric metasurfaces are arrays of sub-wavelength structures that act as a thin layer of artificial material. They are generally lossless and relatively simple to fabricate since only a single structuring step is required. By carefully designing ...

EPFL2020