The strongly spin-momentum coupled electronic states on the surfaces of topological insulators (TIs) exist because of time-reversal symmetry. The theoretical description of these states is fundamentally analogous to a picture used to describe particles known as ‘axions’ theoretically postulated to exist in Nature but never observed. Demonstrating and understanding this conceptual analogy is important for gaining new insights into how our universe works. By interfacing the two opposite surfaces of a TI thin film with different magnetic materials and measuring the magnetic field dependence of the electrical conductance, we show that the ‘axion’ analogy is robust and leads to a new phase of matter known as an ‘axion insulator.’
2D Crystal Consortium - Materials Innovation Platform (2DCC-MIP)
The 2DCC-MIP combines a vibrant in-house research effort focused on transformative advances in the synthesis and characterization of 2D chalcogenide layered materials with a robust external user program that provides access to expertise and state-of-the-art facilities. The 2DCC-MIP platform enables cutting edge research and discovery, across in-house research and the user program, on the synthesis and characterization of 2D chalcogenide materials by a national user community guided by four science drivers: Physics of 2D Systems, Epitaxy of 2D Chalcogenides, Next-generation 2D Electronics, and Advanced Characterization and Modeling.