Theory of Unconventional Magnetism: exploring altermagnets and beyond

This workshop focuses on the theory of emerging unconventional magnetic material classes such as altermagnets, p-wave magnets, and other complex spontaneous magnetic ordered phases with emergent properties. These magnetic phases beyond the conventional s-wave order magnetic paradigm bring new points of views that connect with many fundamental areas of physics and motivated the search for a practical path towards teramagnetic technology.

The concept of altermagnetism and unconventional magnetism beyond the s-wave paradigm has interesting analogies and connections with diverse problems in condensed matter physics, such as unconventional superconductivity, correlated electronic liquid-crystalline phases, multipolar magnetic order, spintronics, and topological phenomena.

The goal of this one-week workshop is to bring together scientists interested in the general problem of altermagnetism who have complementary expertise and experience on these related condensed-matter physics problems. While the workshop will host a few daily talks covering the latest results of this fast-moving field, the focus will be on discussions and direct interactions between the participants, to foster a collaborative environment that will help advance the field and open new research directions.

For videos of the talks and further information, please visit the workshop home page.

Chiral Phonons

Chiral phonons are an emerging field of research focusing on the angular momentum carried by circularly polarized lattice vibrations. While physical mechanisms arising from electronic spin and orbital angular momentum are ubiquitous in solid-state physics, the role of phonon angular momentum has long only been seen in serving as a dissipation channel for the electronic system. In recent years however, an increasing number of phenomena based on phonon angular momentum has been described, including phonon Hall, phonon Zeeman, phonon Barnett, and Einstein-de Haas, as well as phonon spin Seebeck effects. The microscopic origins of these effects have often been found to be universal, which indicates that phonon angular momentum is a quantity of interest in its own right and chiral phonons need to be studied in a holistic approach.

In this workshop, we aim to bring together experts from diverse fields working on phenomena arising from phonon chirality and angular momentum. These include light scattering phenomena in chiral materials, phonon topology, transport phenomena, phonomagnetism, chirality-induced spin selectivity, ultrafast dynamics, and achiral-chiral phase transitions. Discussing chiral phonon physics in an overarching setting will promote collaborations within the community and strengthen our research efforts for the fundamental understanding of angular momentum in solids and the utilization of chiral phonons in potential applications.

For videos of the talks and further information, please visit the workshop home page.

Young Research Leaders Group Workshop: Magnetism in van der Waals materials: current challenges and future directions

Van der Waals materials are a fruitful playground for developing new emergent physical phenomena from bulk down to the two-dimensional limit. Regarding spins, magnetism arises in these systems either naturally —i.e., in van der Waals magnets— or by design —that is, engineering proximity or twist effects in van der Waals heterostructures, even if the starting layers are not magnetic per se!—. Some fundamental properties underlying these magnetic layers are the spin-switching and spin-transport mechanisms, the magneto-elastic coupling or the emergence of topological spin textures (e.g., skyrmions) and topological effects (e.g., the anomalous spin Hall effect), just to mention a few. Understanding these basic properties is key to its integration into devices, impacting in areas like spintronics, magnonics, or opto-electronics.

A characteristic fingerprint of this field is multi-disciplinarity since several disciplines are strongly involved, including chemical growth, advanced physical characterization techniques at the nanoscale (magnetic imaging, magneto-transport measurements, optical characterization, mechanical testing, …), and theoretical modeling, among others. This workshop gathers young researchers working in these areas, offering a holistic vision of the field of magnetism in van der Waals materials, discussing its current challenges, and envisioning future directions.

Overall, we aim to realize new synergetic effects not only between van der Waals layers but, even more importantly, between young researchers, thus creating a forum for future collaborations and scientific exchange.

For videos of the talks and further information, please visit the workshop home page.

Quantum Functionalities of Nanomagnets

Although numerous solid-state platforms are being developed for quantum applications significant challenges remain with respect to control and scalability, making the development of new qubit technologies a foundational activity pursued intensely. An under-explored platform – nanomagnets – is rapidly demonstrating unique features that could further invigorate the advancement of quantum technologies. This workshop aims to discuss the quantum aspects of tailored magnetic platforms, whose main advantage lies in the high degree of control in manipulation, preparation, parameter tunability, and all-magnetic device integration. It will also discuss some of the recent demonstrations of quantum operations using magnets, the discovery of materials with direct relevance to quantum technology, and the development of sensors able to detect magnetic signals with quantum sensitivity. The event will present the state-of-the-art and opportunities for synergy between quantum technology and tailored spin structures, which holds exciting promise for the creation and preservation of quantum information by magnetic quantum states.

For videos of the talks and further information, please visit the workshop home page.

Characterization and control of quantum materials with optical vortex beams

The fascinating physics of optical vortices, in particular light carrying orbital angular momentum (OAM), has resulted in a large interest and currently OAM light can be generated with high precision in a wide photon energy range. Consequently, also the interplay between optical vortices and matter has been investigated in a broad range of phases, from atoms and molecules to solids and plasmas. For example, the study of optical transitions in semiconductors nicely showed the increased complexity of the allowed optical transitions and how the OAM is transferred to the system. This workshop aims to take this a step further and explore how optical vortices can be used to characterize and control complex quantum materials. Through this workshop, it is foreseen to form and bring together a community and form an overview of current and future research endeavors.

Given the exploratory character, the scope of the workshop is purposely kept broad and topics can include, but are not limited to, the following:
• interaction of vortex beams with quantum condensates
• interaction/coupling of the Berry phase associated with the optical OAM vortex with the topological Berry phase in condensed matter
• inducing quantum phase transitions with OAM
• measuring and driving hidden order with vortex beams
• generation and characterization of chiral bosonic modes

For videos of the talks and further information, please visit the workshop home page.

Quantum Geometry and Transport of Collective Excitations in (Non-)Magnetic Insulators

Quantum geometric properties of band structures and their signatures in experiments have driven condensed matter research over the past decades. This SPICE workshop will focus on recent theoretical and experimental advances in the topological properties of bands formed by magnetic and hybrid bosonic excitations. While the topology of electron bands is well understood, with unambiguous experimental tools to probe theoretical predictions, their bosonic analogs pose challenges. Although bosonic topological excitations, such as magnon Chern bands, Weyl and Dirac semimetals, and nodal-line semimetals have emerged, the lack of quantized responses and the ambiguity of thermal Hall and Nernst effects prevent their distinct experimental identification. Furthermore, traditional spectroscopic methods for resolving bosonic modes, such as inelastic neutron scattering, lack the contrast to resolve topological boundary states. One possible route to bring the topological excitations under control is to make use of highly tunable platforms, such as magnonic crystals and stacked van der Waals layers. Additionally, the ease of hybridization of magnonic excitations with phonons, photons, and plasmons can provide novel opportunities to directly probe the topological fingerprint.

With this workshop, we aim to provide a forum where experts and students can discuss the latest developments, challenges, and future directions in topological magnetism. Some exciting challenges that we aim to address include:

-Identify direct experimental signatures for topological bosonic excitations

-Explore the impact of many-body interactions on the quantum geometry of the single particle spectrum and transport

-Identify the microscopic origins of thermal Hall conductivity in magnetic and non-magnetic insulators

-Engineer the quantum geometry and topology of collective excitations by non-Hermitian, non-equilibrium, and Floquet control

For videos of the talks and further information, please visit the workshop home page.