University of Washington
Department of Physics, Department of Materials Science and Engineering
University of Washington, Seattle WA
Since the discovery of graphene, the family of two-dimensional (2D) materials has grown to encompass a broad range of electronic properties. However, until recently 2D crystals with intrinsic magnetism were still lacking. Such crystals would enable new ways to study 2D magnetism by harnessing the unique features of atomically-thin materials, such as electrical control for magnetoelectronics and van der Waals engineering for novel interface phenomena. In this talk, I will describe our recent magneto-optical spectroscopy experiments on van der Waals magnets, chromium(III) iodide CrI3. I will first demonstratethe existence of isolatedmonolayer semiconductor with intrinsic Isingferromagnetism. I will then show thelayer number-dependent magnetic phases. The magnetic ground state evolves from being ferromagnetic in a monolayer, to antiferromagnetic in a bilayer, and back to ferromagnetic in atrilayer and thin bulk. Lastly, I will discuss the emerging spin phenomena in monolayer WSe2/CrI3 ferromagnetic semiconductor heterostructures, including ferromagnetic control of valley pseudospin in WSe2 via large magnetic exchange field, and optical analog of giant magnetoresistance effect.
Bio: Xiaodong Xu is a Boeing Distinguished Associate Professor in the Department of Physics and the Department of Materials Science and Engineering at the University of Washington. He received his PhD (Physics, 2008) from the University of Michigan and then performed postdoctoral research (2009-2010) at the Center for Nanoscale Systems at Cornell University. His nanoscale optoelectronics group at University of Washington focuses on creation, control, and understanding of novel device physics based on two-dimensional quantum materials. Selected awards include DAPRA YFA, NSF Early Career Award, DoE Early Career Award, Cottrell Scholar Award, University of Washington Innovation Award, and IUPAP Young Scientist Prize in Semiconductor Physics.