Events at Physics |
Events on Monday, May 4th, 2026
- Academic Calendar
- Exams
- Abstract: *Note: actual end time may vary.* CONTACT: admin@secfac.wisc.edu
- Preliminary Exam
- Cosmological Information Recovery from Large-Scale Structure
- Time: 10:00 am - 12:00 pm
- Place: B343 Sterling
- Speaker: Shihui Zang, Physics PhD Graduate Student
- Abstract: Large-scale structure (LSS) provides powerful and complementary constraints on cosmology, but much of its information is obscured by nonlinear gravitational evolution, galaxy bias, redshift-space distortions, and survey systematics. This prelim exam focuses on methods to recover cosmological information from LSS, with emphasis on two themes.
- Host: Moritz Munchmeyer
- Preliminary Exam
- Creating new low-switching orderings by stacking order engineering of 2D materials
- Time: 1:30 pm - 3:30 pm
- Place: B343 Sterling
- Speaker: Carter Fox, Physics PhD Graduate Student
- Abstract: By altering the stacking order of 2D van der Waals (vdW) materials, many new ferroic, strongly correlated and topological orderings emerge with exotic electrical, optical and magnetic properties. Owing to the weak vdW interlayer bonding, such highly flexible and energy-efficient stacking order engineering has transformed the design of quantum properties in 2D materials. In this talk, I present two advances enabled by stacking order engineering. First, I demonstrate the creation of a sliding multiferroic by stacking inherently non-polar layers of the 2D magnet CrI3 into a polar stacking order. Using combined optical and electrical transport characterization techniques, emergent sliding ferroelectricity is shown to interplay with interfacial ferromagnetism via interlayer spin-polarized charge transfer. This unique magnetoelectric coupling mechanism leads to non-volatile magnetic switching at zero external magnetic field, driven by voltages as low as 0.4 V across the CrI3. Second, I introduce a new domain superposition mechanism to engineer topological polar textures based on the orthogonal stacking of displacive vdW ferroelectrics. This concept is demonstrated with NbOI2 layers, where we directly observe polar vortices and related textures at overlapping domain walls via 4D-STEM. Furthermore, second harmonic generation circular dichroism reveals a robust chiroptical response, and we show that the macroscopic chiral state is reversibly controlled in four terminal devices. Together, these results highlight stacking order engineering as a versatile route to programmable multiferroic and topological states in vdW materials, opening pathways toward next generation electronic, spintronic, and photonic technologies.
- Host: Jun Xiao