Materials Science and Engineering Seminar

Engineering quantum materials at the atomic scale — through epitaxial growth or mechanical exfoliation — has driven a remarkable era of discovery in 2D electronics and quantum physics. A new frontier is now emerging: using ultrafast light pulses to create transient phases of matter not just in space, but also in time. This direction calls for new materials synthesis strategies, characterization tools, and an integration between materials design and ultrafast optical control. Shuolong Yang will present two recent examples from his group at the University of Chicago. First, they grow monolayer MnBi₂Te₄ by molecular beam epitaxy and show that photoexcitation drives it into an exciton condensate — a collective quantum state of bound electron-hole pairs. Tracked by time- and angle-resolved photoemission spectroscopy (tr-ARPES), this condensate exhibits a 2D superfluid which persists up to 280 K. It can be continuously tuned between a fermionic (BCS-like) and bosonic (BEC-like) regime, offering a controllable platform for studying quantum phase transitions in 2D materials. Second, they integrate topological insulator Bi₂Se₃ with a photonic crystal cavity to achieve spatiotemporal control over its electronic structure.