3:45–5:00 pm
GCIS W301/303 929 E. 57th St
Speaker: Assoc. Prof. Matthew Yankowitz, Dept. of Physics, University of Washington
Host: Asst. Prof. Andrew Higginbotham, Dept. of Physics (ahigginbotham@uchicago.edu)
Quantum alchemy in the topological flat bands of rhombohedral graphene
Quantum materials provide a rich setting for unconventional superconductivity, strong correlations, and nontrivial topology. Historically, accessing distinct quantum phases has required synthesizing different materials. Two-dimensional van der Waals systems have recently changed what is possible. I will discuss rhombohedral graphene, a crystalline system in which a wide array of quantum states are accessible by electrostatic gating. This purely carbon-based material supports a form of quantum alchemy, where conventionally distinct states of matter such as superconductivity and magnetism can be accessed within a single sample. In intrinsic rhombohedral graphene, the electronic wavefunction concentrates on the outer crystal faces and is strongly suppressed in the bulk. We observe unconventional superconductivity emerging from this surface-polarized semimetal, with the spatial wavefunction geometry acting as a new control knob for pairing. An in-plane magnetic field greatly broadens the superconducting region and drives it far beyond the Pauli limit, suggestive of spin-triplet pairing. The same material also hosts quantized anomalous Hall states at zero magnetic field. I will close by previewing new opportunities in this system, including strain and pressure control and the possibility of drawing electrostatic boundaries between phases
About the JFI Colloquium: The James Franck Institute Colloquium is a monthly event inviting distinguished scholars from research institutions around the globe to share creative, groundbreaking research at the intersection of chemistry, physics, and materials science. As an interdisciplinary institution, the JFI welcomes researchers and students from a wide variety of scientific disciplines to attend and partake in lively discussion. Colloquium speakers are nominated by JFI faculty and selected annually by the colloquium committee. Find the full calendar on the JFI website.