Recent advancements in van der Waals (vdW) materials have significantly impacted spintronic research, contributing to the development of devices such as magnetic tunnel junctions (MTJs), spin valves, and spin filters, as well as advancing fundamental studies on magnetic properties in reduced physical dimensions. The unique characteristics of vdW-assembled spintronic devices, including atomically flat interfaces and the ability to engineer material properties through proximity effects, enable the efficient induction of spin-orbit coupling, exchange polarization, and magnetic anisotropy at interfaces. These properties extend the applications of spintronics by reducing spin-dephasing scatterings and improving spin injection and detection efficiency. Despite several imminent challenges, including the discovery of new materials suitable for room-temperature applications and scalable synthesis methods, vdW materials hold great promise for next-generation spintronic devices, offering low-power, high-efficiency performance, and potential integration with quantum technologies.

In this article, we provide an overview of theoretical and computational methods for studying magnetic van der Waals materials with special emphasis on first-principles computations and their application. First, we discuss the issues, such as how to properly consider electronic interactions via weak interlayer couplings, the exchange-correlation functional used for density-functional theory calculations, Hund physics, and dynamical mean-field theory methods. We then switch gears to the optical properties of magnetic van der Waals materials with specific emphasis on intriguing excitons and the interplay between spin and orbital degrees of freedom. Finally, we discuss chiral phonons and magnon-phonon interactions.

Optical spectroscopic tools are extensively utilized in the study of van der Waals magnetic materials. The small volume of atomically thin specimens renders traditional measurement tools such as magnetic susceptibility measurements or neutron scattering experiment inadequate. Optical measurements, on the other hand, can have a spatial resolution on the order of the focus size of the probing beam and are often sensitive enough to probe atomically thin samples. Several optical spectroscopy techniques have demonstrated to be capable of probing various physical properties of these materials. Raman spectroscopy, terahertz spectroscopy, photoluminescence, optical absorption, and second harmonic generation have been applied to various magnetic van der Waals materials and have shown to be particularly powerful in the studies of antiferromagnetic van der Waals materials.

This article traces the 15-year journey (2010–2025) of pioneering research on van der Waals (vdW) magnets in Korea, starting from the original idea of “magnetic graphene”. I recount my early failures with oxide systems, and then the discovery of TMPS3 compounds as model 2D magnets in the early 2010s. Crucially, the first public talks were given in 2015–2016, including one at the 2015 Korean Physical Society Fall meeting, along with the publication of four papers in 2016. Notably, the FePS3 paper verified Onsager’s 2D Ising model experimentally, which established the foundation of the field. Our work and research done by other groups triggered a global interest in the field, making vdW magnetism a major topic in condensed matter and materials science worldwide. Finally, I end with my personal reflections on the future direction of the field.

This year’s Nobel Prize in Physics was awarded for the experimental demonstration of macroscopic quantum tunneling and energy quantization of the phase particle defined in a Josephson junction. This groundbreaking work extended quantum mechanics beyond microscopic systems into the macroscopic realm. By revealing that Josephson junctions could function as superconducting artificial atoms, the discovery enabled researchers to engineer and control quantum states with unprecedented precision, thereby providing a crucial foundation for the subsequent development of superconducting quantum computers.

The Nobel laureates of this year have devised an experiment to observe macroscopic quantum tunneling in an electrical circuit made of superconductors. This monumental discovery has sparked numerous innovations and ultimately earned the three pioneers the Nobel prize. Afterwards, superconducting circuits play a key role in the proliferation of quantum technology in the 21st century. Especially, in the heart of the 2nd quantum revolution, quantum information technology is based on the radical development of the quantum computers. Superconducting Josephson junction devices has been the most advanced technology that has been picked up by the global tech giants in quantum computing. I will briefly review how the superconducting quantum chips and the macroscopic quantum effect had led innovation in quantum technology afterwards.

It is widely believed that the microscopic, that is, atomic-scale or smaller, world is governed by quantum mechanics while the macroscopic world, where our direct and daily experiences reside, is governed by classical mechanics. But why? Why do we not observe quantum phenomena such as quantum tunneling and quantum superposition in the macroscopic world? Where is the boundary between the microscopic and macroscopic worlds when it comes to the governing physical principles? Macroscopic quantum phenomena were first examined theoretically by A. Leggett in the 1970s. This boldly audacious idea was experimentally demonstrated in a series of groundbreaking works on Josephson junctions by John Clarke, Michel Devoret, and John Martinis in 1985, that have been celebrated by the 2025 Nobel Prize in Physics. The trio’s work spurred the development of various qubit types based on superconducting circuits, ultimately leading to the current advancement of superconducting quantum computers.

Ultrafast control of light–matter interactions is a central theme in photonics, enabling access to non-equilibrium collective phenomena. Modulating the refractive index on sub-picosecond scales reveals fundamental limits of optical response, however conventional electro-optic and carrier-based schemes remain constrained by intrinsic speed limits. Ferroelectric hafnium oxide (HfO2) has recently attracted attention as a robust platform, maintaining polarization stability at nanometer dimensions while remaining compatible with modern material processing. Current directions focus on driving polarization dynamics with ultrafast optical fields, especially in the terahertz and mid-infrared regimes, to probe dielectric responses at the ultimate temporal and spatial limits. These approaches open pathways toward clarifying the intrinsic switching mechanisms of ferroelectrics and exploring novel routes for light–matter control in complex oxides.

Ferroelectric materials are emerging as promising candidates for high-performance optical modulators in integrated photonics. Their intrinsic Pockels effect enables direct and ultrafast control of the refractive index, allowing efficient conversion of electrical signals into optical modulation. This article reviews the operating principles of optical modulators, contrasting thermal and free-carrier approaches with ferroelectric electro-optic modulation, and discusses recent advances toward their integration with silicon photonics platforms.