2026 APS global summit talks from our group.
Quasiparticle microscope at single quantum hall impurities
Wed. March 18, 12:48 — 1:00 p.m.
Convention Center,Meeting Room 405
Presenter: Yiming Sun
Part of MAR-M35 STM and NanoSQUID Imaging of Layered Graphene Structures
Quantum Hall systems host highly correlated and degenerate electronic states, where exotic quasiparticles such as fractionalized anyons can emerge. However, conventional bulk measurements lack the spatial resolution to probe them individually. Using scanning tunneling spectroscopy (STS) on an ultraclean graphene device under a high magnetic field, we directly visualize quantum Hall quasiparticles in real space near single charged defects. The Coulomb potential of these defects lifts the Landau-level degeneracy, separating orbits with different angular momentum in energy and thereby enabling their individual imaging. When quasiparticles are bound to the impurity potential, distinct spectral features arise, encoding the number and type of bound states. By analyzing the spectral weight, we visualize localized quasiparticles in real space—realizing a quasiparticle microscope that reveals their distribution down to the single-defect limit and opens a pathway to observe and manipulate non-Abelian anyons.
Superconductivity and Ferroelectric Orbital Magnetism in Semimetallic Rhombohedral Hexalayer Graphene
Tue. March 17, 12:36 — 12:48 p.m.
Convention Center,Meeting Room 201
Presenter: Jinghao Deng
Part of MAR-G24 Novel Superconductivity in Two-Dimensional Systems
Rhombohedral multilayer graphene has emerged as a promising platform for exploring correlated and topological quantum phases, enabled by its Berry-curvature-bearing flat bands. While prior work has focused on separated conduction and valence bands, we probe the extensive semimetallic regime of rhombohedral hexalayer graphene. We survey a rich phase diagram dominated by flavor-symmetry breaking and reveal an electric-field-driven band inversion through fermiology. Near this inversion, we find a superconducting-like state confined to a region with emergent electron and hole Fermi surfaces. In addition, two multiferroic orbital-magnetic phases are observed: a ferrovalley state near zero field and a ferroelectric state at large fields around charge neutrality. The latter shows electric-field-reversible magnetic hysteresis, consistent with a ΔP·M multiferroic order parameter.
Signatures of tunable magnetic-field-induced superconductivity and their large Pauli violation in hexalayer rhombohedral graphene
Tue. March 17, 12:48 — 1:00 p.m.
Convention Center,Meeting Room 201
Presenter: Jiabin Xie
Part of MAR-G24 Novel Superconductivity in Two-Dimensional Systems
Rhombohedral multilayer graphene systems have emerged as a unique platform to host multiple unconventional superconducting behaviors. Here, we report signatures of in-plane magnetic fields induced superconductivity in hexalayer rhombohedral graphene near a symmetry-breaking transition. The onset and critical magnetic field for the field-induced superconductivity can be continuously tuned by electric fields with a critical magnetic field maxima > 14 T which is far beyond the Pauli limit. Fermiology analysis reveals that these superconducting states derived from the Lifshitz transition at the symmetry breaking phase boundary. The experimental results suggest a highly unconventional superconductivity behavior in hexalayer rhombohedral graphene that possibly possesses a spin-triplet order parameter.
Xiaomeng Liu awarded 2026 Sloan Fellowship
We are happy to announce that Prof. Xiaomeng Liu has won 2026 Sloan Research Fellowships from the Alfred P. Sloan Foundation. https://news.cornell.edu/stories/2026/02/five-cornell-named-2026-sloan-research-fellows
First paper submitted
We have submitted our first manuscript exploring the correlated semimetal regime of rhombohedral six-layer graphene (https://arxiv.org/abs/2508.15909). We revealed a rich semimetallic phase diagram ruled by flavor polarized bands. In particular, we uncovered superconductivity originating from emergent fermi surfaces and a distinct orbital ferromagnetism with magnetic hysteresis polarity controlled by electric fields. This work is currently under review.
Xiaomeng Liu received NSF CAREER Award
We are very excited to receive the CAREER (Faculty Early Career Development Program) award from the NSF.
With this five year grant, Liu group will develop a novel microscopic approach to identity and manipulate anyons, exotic emerging particles of topological materials that could pave a new path to quantum computing.
Integrated to the science objective, we will work with Ithaca physics bus to disseminate quantum physics through hand-on demonstrations, make quantum material research more accessible with online knowledge sharing, and modernize advanced lab course at Cornell.
News link: https://news.cornell.edu/stories/2025/03/five-early-career-professors-win-nsf-development-awards.
Our STM is here!
We are excited to get our 300mK 15T UHV STM installed.
The table/chamber is heavy! Thanks Jason for helping us move it to the lab.
The table to be united with the cryostat.
Another view of the assembled chambers.
How often one get to see this?
New Oxford ProteoxMX dilution fridge being installed. Reached 8.75mK on MC.
Liu group receive New Frontier Grant
We are excited to receive the New Frontier Grant from Cornell College of Arts & Sciences. The New Frontier Grants program aims to enable novel, high-risk/high-impact research projects with compelling visions for transformative advances in the arts and humanities, social sciences, and natural sciences. In this projects, we aim to develop a high energy- and spatial-resolution spin sensor to uncover hidden magnetic orders with zero global magnetization, such as Skyrmion lattices and quantum spin liquids. This unique single spin microscope will be enabled by combining scanning tunneling microscope (STM) with recently emerged van der Waals materials and devices. With this technique, we will be able to visualize spin textures and probe spin excitations.
This two year funding will support our early stage effort in developing this new technique. We very much appreciate the support from Cornell A&S and donors who made this program possible.
News Link: https://as.cornell.edu/news/projects-funded-2024-new-frontier-grants-look-toward-future
First device
From exfoliation, stacking, to nano-fabrication, we have established the pipeline for creating vdW devices. This marks a mile stone—achieving one of the key technical pillars of the lab.
Device created by Chang Chang
First stack made!
Chang Chang made the first stack of the lab! It is a simple BN-graphene-BN but it only going to get better and more sophisticated from here.
We are looking for new members!
This is an exciting time to join our team as our lab takes shape. You'll have the unique opportunity to explore the depths of experimental physics, involving tasks like setting up a dilution fridge, adapting data acquisition programs and interfacing them with instruments, and customizing STM for 2D material samples. This experience will provide you with a comprehensive understanding of condensed matter experiments and enhance your problem-solving skills.
Considering the relatively short setup timeline, your contributions will undoubtedly be rewarding, and you'll embark on exciting projects right from the beginning. As one of the founding members of our group, you'll collaborate closely with the PI and have the opportunity to shape the group's culture and direction.
If these prospects align with your interests and aspirations, we encourage you to explore our opportunity page and reach out without hesitation.
Liu Lab is Launched at Cornell
It all begins with an idea.
On August 1, 2023, I started on my journey at Cornell University—an incredibly supportive, stimulating, and beautiful place. As of now, we have placed orders for all major pieces of equipment, including the Unisoku USM 1300 STM and the Oxford Proteox dilution fridge, among others. Lab renovation is in progress, with the expectation of gaining the capability to fabricate van der Waals (vdW) samples at the beginning of 2024. And we anticipate the completion of the dilution fridge and STM installation in the latter half of 2024.
We looking forward to the completion of our lab and beginning our experiments. Today, we are thrilled to launch our lab website, and I invite you to stay tuned for the exciting results we will be sharing in the near future.
