Abstract: Hybrid systems based on the interaction of magnons—the quanta of collective spin excitations in magnetic materials—with spatially confined electromagnetic waves (cavity modes) or elastic vibrations (phonons) enable novel architectures that benefit from the combination of complementary physical systems. In this talk, I will discuss recent advances in cavity magnonics and magnon-phonon systems, which is being developed for integration into future quantum technologies.

Abstract: Recent experiments show that the ground state of some layered materials with localized moments is in close proximity to the Kitaev spin liquid, calling for a proper model to describe the measurements. The Kitaev-Hubbard model is the minimal model that captures the essential ingredients of these systems; it yields the Kitaev-Heisenberg spin model at the strong coupling limit and contains the charge fluctuations present in these materials as well. Despite its relevance,  the phase diagram of the Kitaev-Hubbard model has not been rigorously revealed yet. In this work, we study the full phase diagram of the Kitaev-Hubbard model using the Z_2 slave-spin mean-field theory as well as the auxiliary field quantum Monte Carlo on rather large systems and at low temperatures. The Mott transition is signaled by a vanishing quasiparticle weight evaluated using the slave-spin construction. Moreover, we demonstrate that there are multiple magnetic phase transitions within the Mott phase including magnetically ordered phases and most notably a quantum spin liquid phase for 0.99 <  t'/t < 1.12 at U=5t. 

Abstract: TiSe₂, a layered transition metal dichalcogenide, exhibits a well-known charge density wave (CDW) transition that profoundly alters its electronic and optical properties. In this talk, we explore the interplay between CDW order and both plasmonic and thermophotonic responses in TiSe₂. We show that the formation of the CDW gap modifies the plasmonic excitation spectrum, reflecting changes in carrier dynamics and collective charge behavior. Simultaneously, we discuss how thermal emission evolves across the CDW transition, revealing characteristic spectral features linked to entropy reduction and electronic reconstruction. Together, these findings provide a unified picture of how CDW physics governs light–matter and heat–radiation interactions in TiSe₂, offering new opportunities for dynamic control in optoelectronic and photonic systems.

Abstract: When a two-dimensional molecular network self-assembles on a metallic surface, the surface electrons of the substrate become confined within the network's pores. Besides surface state confinement, laterally protruding organic states can collectively hybridize at the smallest pores into superatom molecular orbitals. Each pore can host a superatom, and the resulting two-dimensional array of superatoms provides an ideal platform for investigating quantum electron scattering phenomena. While both surface and pore states can coexist within nanocavities, their interactions lead to interesting collective behavior at the nanoscale. Using a combination of scanning tunneling microscopy and spectroscopy, density functional theory calculations, and electron plane wave expansion simulations, we show how several types of pore states coexist within the nanocavities of a two-dimensional halogen-bonding multiporous network grown on Ag(111). The resonance between the superatom molecular orbitals and confined surface states reveals the control exerted by two-dimensional nanoporous systems over surface electronic structures.

Abstract: The recent discovery of two-dimensional (2D) layered magnets has opened new avenues for investigating exotic magnetic excitations and emergent topological phenomena. A key open question is the microscopic origin of the magnon bandgap at the K symmetry points of the magnetic Brillouin zone in certain vdW magnets, such as CrI₃.

Flat bands have long attracted significant attention in condensed matter physics due to their ability to host strongly correlated electrons. Today, two-dimensional materials provide an ideal platform for the emergence of these bands and enable the exploration of various collective phenomena. Common structures for studying flat-band physics include graphene and transition metal dichalcogenide heterostructures under twist, as well as Kagome and Lieb lattices. In this presentation, we investigate the emergence of flat band in a monolayer of NoOCl₂, despite the absence of typical conditions. We also demonstrate how flat band can lead to magnetization and also discuss the exciton physics within this system.

Abstract: Today, first-principles approach is widely used to study electron-phonon interactions and their impact on the transport properties of materials. Emphasis is placed on how crystal symmetry governs electron-phonon coupling, particularly in relation to flexural phonon modes in the presence of mirror symmetry. We examine how doping and Fermi surface topology influence the emergence of superconductivity and charge density wave phases in layered materials, utilizing nonadiabatic effects and highlighting the crucial role of Kohn anomalies in accurately describing phonon behavior and electron-phonon coupling. Furthermore, carrier mobility and scattering mechanisms are analyzed, with a focus on the dominant role of optical phonons. These findings collectively underscore the importance of symmetry, electronic structure, and phonon dynamics in determining the transport behavior of two-dimensional systems.