Publications associées à Skyrmion

Experimental observation of topological transition in linear and nonlinear parametric oscillators

Romain Christophe Rémy Fleury, Benjamin Apffel

Parametric oscillators are examples of externally driven systems that can exhibit two stable states with opposite phase depending on the initial conditions. In this work, we propose to study what happens when the external forcing is perturbed by a continuo ...

2024

Ultrafast control of emergent quantum matter probed by electron microscopy

Benoît Guilhem Michel Binh Truc

In the quest for controlling materials' properties, light as an external stimulus has a special place as it can create new states of matter and enable their ultrafast manipulation. In particular, spintronics, an exciting emergent field relying on the elect ...

EPFL2023

Unconventional Flat Chern Bands and 2e Charges in Skyrmionic Moire Superlattices

Oleg Yazyev, Yifei Guan

The interplay of topological characteristics in real space and reciprocal space can lead to the emergence of unconventional topological phases. In this Letter, we implement a novel mechanism for generating higher-Chern flat bands on the basis of twisted bi ...

AMER CHEMICAL SOC2023

Seeding and Emergence of Composite Skyrmions in a van der Waals Magnet

Klaus Kern, Marko Burghard, Lukas Powalla

Topological charge plays a significant role in a range of physical systems. In particular, observations of real-space topological objects in magnetic materials have been largely limited to skyrmions - states with a unitary topological charge. Recently, mor ...

Wiley-V C H Verlag Gmbh2023

Chiral magnetohydrodynamics with zero total chirality

Kohei Kamada, Jennifer Waltraud Schober

We study the evolution of magnetic fields coupled with chiral fermion asymmetry in the framework of chiral magnetohydrodynamics with zero initial total chirality. The initial magnetic field has a turbulent spectrum peaking at a certain characteristic scale ...

American Physical Society2023

Skyrmion Control and Phase Transitions in Cu2OSeO3

Thomas Schönenberger

Magnetic skyrmions are nanometric and non-trivial spin textures with non-zero topological charge. Their robustness against perturbations and the possibility to control them using external stimuli make them ideal candidates for future spintronic application ...

EPFL2022

Topological aspects of non-centrosymmetric magnets

Priya Ranjan Baral

The concept of chirality has been influencing many branches of physics for centuries. On the other hand, study of topology and related concepts have recently been introduced to the physics community. Exotic quasiparticles, such as magnetic skyrmions emerge ...

EPFL2022

Square and rhombic lattices of magnetic skyrmions in a centrosymmetric binary compound

Jonathan White, Le Yu

Magnetic skyrmions are topologically stable swirling spin textures with particle-like character, and have been intensively studied as a candidate of high-density information bit. While magnetic skyrmions were originally discovered in noncentrosymmetric sys ...

Nature Research2022

Imaging the Ultrafast Coherent Control of a Skyrmion Crystal

Henrik Moodysson Rønnow, Dirk Grundler, Arnaud Magrez, Fabrizio Carbone, Ivan Madan, Ping Che, Alexey Sapozhnik, Priya Ranjan Baral, Simone Gargiulo, Thomas Schönenberger

Exotic magnetic textures emerging from the subtle interplay between thermodynamic and topological fluctuation have attracted intense interest due to their potential applications in spintronic devices. Recent advances in electron microscopy enable the imagi ...

American Physical Society2022

Real space and reciprocal space investigations of the spin dynamics in skyrmion-hosting materials

Le Yu

Magnetic skyrmions are whirl-like spin configurations with particle-like properties protected by non-trivial topology. Due to their unique spin structures and dynamical properties, they have attracted tremendous interests over the past decade, from fundame ...

EPFL2022

Single Skyrmion Generation via a Vertical Nanocontact in a 2D Magnet-Based Heterostructure

Klaus Kern, Marko Burghard, Lukas Powalla

Skyrmions have been well studied in chiral magnets and magnetic thin films due to their potential application in practical devices. Recently, monochiral skyrmions have been observed in twodimensional van der Waals magnets. Their atomically flat surfaces an ...

AMER CHEMICAL SOC2022

Thermal Evolution of Dirac Magnons in the Honeycomb Ferromagnet CrBr3

Andreas Martin Läuchli Herzig, Bruce Normand, Christian Rüegg

CrBr3 is an excellent realization of the two-dimensional honeycomb ferromagnet, which offers a bosonic equivalent of graphene with Dirac magnons and topological character. We perform inelastic neutron scattering measurements using state-of-the-art instrume ...

2022

Probing the topology of the quantum analog of a classical skyrmion

Frédéric Mila, Jeanne Colbois

In magnetism, skyrmions correspond to classical three-dimensional spin textures characterized by a topological invariant that keeps track of the winding of the magnetization in real space, a property that cannot be easily generalized to the quantum case si ...

2021

Helimagnons and Skyrmion Dynamics in Cu2OSeO3 and Fe/Gd Multilayers Explored by Brillouin Light Scattering and X-ray Microscopy

Ping Che

Spin dynamics in skyrmion hosting materials provide novel functionality in magnonics because of the formation of a novel magnon band structure and the nanoscale sizes of magnetic skyrmions. In this thesis, we explore the spin dynamics in the chiral magnet ...

EPFL2021

S-matrix bootstrap for effective field theories: massless pions

João Miguel Augusto Penedones Fernandes, Andrea Guerrieri

We use the numerical S-matrix bootstrap method to obtain bounds on the two leading Wilson coefficients (or low energy constants) of the chiral lagrangian controlling the low-energy dynamics of massless pions. This provides a proof of concept that the numer ...

Springer Nature2021

Tunable cooperativity in coupled spin-cavity systems

Helmuth Berger

We experimentally study the tunability of the cooperativity in coupled spin-cavity systems by changing the magnetic state of the spin system via an external control parameter. As a model system, we use the skyrmion host material Cu2OSeO3 coupled to a micro ...

AMER PHYSICAL SOC2021

Vital role of magnetocrystalline anisotropy in cubic chiral skyrmion hosts

Henrik Moodysson Rønnow, Jonathan White

Magnetic anisotropy is anticipated to govern the formation of exotic spin textures reported recently in cubic chiral magnets, like low-temperature tilted conical and skyrmion lattice (SkL) states and metastable SkLs with various lattice geometry. Motivated ...

NATURE RESEARCH2021

Metastable skyrmion lattices governed by magnetic disorder and anisotropy in beta-Mn-type chiral magnets

Henrik Moodysson Rønnow, Jonathan White

Magnetic skyrmions are vortexlike topological spin textures often observed in structurally chiral magnets with Dzyaloshinskii-Moriya interaction. Among them, Co-Zn-Mn alloys with a beta-Mn-type chiral structure host skyrmions above room temperature. In thi ...

AMER PHYSICAL SOC2020

Room-temperature skyrmion phase in bulk Cu2OSeO3 under high pressures

Helmuth Berger

A skyrmion state in a noncentrosymmetric helimagnet displays topologically protected spin textures with profound technological implications for high-density information storage, ultrafast spintronics, and effective microwave devices. Usually, its equilibri ...

National Academy of Sciences2020

Melting of a skyrmion lattice to a skyrmion liquid via a hexatic phase

Henrik Moodysson Rønnow, Arnaud Magrez, Marco Cantoni, Fabrizio Carbone, Ping Huang, Thomas Schönenberger

While in 3D materials melting is a single, first-order phase transition, in 2D systems, it can also proceed via an intermediate phase. For a skyrmion lattice in Cu2OSeO3, magnetic field variations can tune this quasiparticle 2D solid into a skyrmion liquid ...

Nature Publishing Group2020