Tunable magnetism with emerging quantum phenomena in two-dimensional magnets

Two-dimensional (2D) magnets with atomically thin nature provide an ideal material platform for exploring 2D magnetism, whose physical paradigm is fundamental in science. Their tunable magnetic order in the 2D limit, interplaying with strong fluctuation, correlation, and topology, further brings enormous opportunities to explore exotic quantum phenomena and associated device applications that were previously out of reach. Here, we give a perspective on tuning 2D magnetism with emerging quantum phenomena in 2D magnets. After a summary to the material landscape and probing methodologies of 2D magnetism, we highlight its multidimensional tuning in 2D magnets, via knobs ranging from layer number, light, electrical field, to twist engineering, and so on. We further present how such control can be harnessed for engineering various exotic quantum phenomena, with emphasis on electron tunneling, quantum-geometry-related transport, and spin-exciton interactions. An outlook on challenges and opportunities of 2D magnets is also given to unlock their unprecedented possibilities for both fundamental science and applied technologies.