Emergent quantum materials

The term quantum materials refers to materials whose properties are principally defined by quantum mechanical effects at macroscopic length scales and that exhibit phenomena and functionalities not expected from classical physics. Some key characteristics include reduced dimensionality, strong many-body interactions, nontrivial topology, and noncharge state variables of charge carriers. The fi eld of quantum materials has been a topical area of modern materials science for decades, and is at the center stage of a wide range of modern technologies, ranging from electronics, photonics, energy, defense, to environmental and biomedical sensing. Over the past decade, much research effort has been devoted to the development of quantum materials with phenomena and functionalities that manifest at high temperature and feature unprecedented tunability with atomic-scale precision. This thriving research field has witnessed a number of seminal breakthroughs and is now poised to rise to the challenges in a new age of quantum information science and technology. This issue summarizes and reviews recent progress in selected topics, and also provides perspective for the future directions of emergent quantum materials in the years to come.