Condensed Matter/Materials & Biological Physics Seminar with Tiancheng Song on Discovering and Engineering Two-Dimensional Magnetism and Superconductivity

Understanding and manipulating macroscopic quantum phenomena such as superconductivity and magnetism are crucial for future quantum science and technology. Two-dimensional (2D) materials and their van der Waals (vdW) heterostructures offer a promising platform to achieve this goal due to their exceptionally broad tunability. In this talk, I will highlight the potential of such a platform through two outstanding examples: 2D magnetism and 2D superconductivity. In the first part, I will talk about emergent phenomena enabled by the vdW nature of 2D magnets, especially novel moiré magnetism by twisting two layers of 2D magnets. In the second part, I will introduce a new probe to detect superconducting fluctuations down to millikelvin temperatures based on thermoelectric measurements of a monolayer nanoflake. I will discuss surprisingly unusual vortex Nernst signals, which reveal an unconventional superconducting quantum criticality in an electrically tunable 2D superconductor. These results highlight unique opportunities for discovering and engineering new quantum phases in two dimensions.