Colloquium- Minhao He (Princeton)- Visualizing and engineering quantum states of matter in vdW materials

Minaho He standing in front of a wall of lab equipment

February 13, 2025

10:30AM - 11:30AM

1080 Physics Research Building

Add to Calendar 2025-02-13 10:30:00 2025-02-13 11:30:00 Colloquium- Minhao He (Princeton)- Visualizing and engineering quantum states of matter in vdW materials Dr. Minhao HePrinceton UniversityVisualizing and engineering quantum states of matter in vdW materialsLocation: 1080 Physics Research BuildingFaculty Host: Fengyuan Yang Abstract: The study of electronic interaction is pivotal to understanding strongly correlated states and their collective excitations. Isolated flat bands provide ideal settings for such investigations thanks to their simple band structure. They can be realized in vdW materials either under a strong magnetic field, forming Landau levels, or at zero magnetic field with presence of a large moiré superlattice. In this talk, I will first highlight the recent direct visualization of the Wigner crystal in the Landau level of Bernal-stacked bilayer graphene, using scanning tunneling microscopy (STM). I will discuss how STM, combined with atomically clean vdW devices, reveals the quantum nature of electrons and provides microscopic insights into their behavior. In the second part, I will talk about recent advances in flat-band engineering, using graphene-based moiré superlattices as a case study. I will demonstrate the wide tunability of these flat bands and the rich interplay of flavor symmetry breaking and topological properties in the resulting quantum states. Finally, I will conclude by highlighting new opportunities enabled by zero-field topological flat bands engineered in moiré vdW materials. Bio: Dr. Minhao He is currently a Princeton Quantum Initiative postdoc fellow working with Prof. Ali Yazdani in the Department of physics at Princeton University. His current work focuses on using scanning tunneling microscopy to directly visualize and explore the interacting electronic states emergent in the atomically thin vdW devices. He received his Ph.D. in Physics from the University of Washington in 2022, under the supervision of Prof. Xiaodong Xu, where he worked on both transport measurements of strongly correlated states in the flat topological bands of moiré graphene, and optical studies of various types of excitons in the monolayer semiconductors. 1080 Physics Research Building OSU ASC Drupal 8 ascwebservices@osu.edu America/New_York public

2025-02-13 10:30:00 2025-02-13 11:30:00 Colloquium- Minhao He (Princeton)- Visualizing and engineering quantum states of matter in vdW materials Dr. Minhao HePrinceton UniversityVisualizing and engineering quantum states of matter in vdW materialsLocation: 1080 Physics Research BuildingFaculty Host: Fengyuan Yang Abstract: The study of electronic interaction is pivotal to understanding strongly correlated states and their collective excitations. Isolated flat bands provide ideal settings for such investigations thanks to their simple band structure. They can be realized in vdW materials either under a strong magnetic field, forming Landau levels, or at zero magnetic field with presence of a large moiré superlattice. In this talk, I will first highlight the recent direct visualization of the Wigner crystal in the Landau level of Bernal-stacked bilayer graphene, using scanning tunneling microscopy (STM). I will discuss how STM, combined with atomically clean vdW devices, reveals the quantum nature of electrons and provides microscopic insights into their behavior. In the second part, I will talk about recent advances in flat-band engineering, using graphene-based moiré superlattices as a case study. I will demonstrate the wide tunability of these flat bands and the rich interplay of flavor symmetry breaking and topological properties in the resulting quantum states. Finally, I will conclude by highlighting new opportunities enabled by zero-field topological flat bands engineered in moiré vdW materials.  Bio: Dr. Minhao He is currently a Princeton Quantum Initiative postdoc fellow working with Prof. Ali Yazdani in the Department of physics at Princeton University. His current work focuses on using scanning tunneling microscopy to directly visualize and explore the interacting electronic states emergent in the atomically thin vdW devices. He received his Ph.D. in Physics from the University of Washington in 2022, under the supervision of Prof. Xiaodong Xu, where he worked on both transport measurements of strongly correlated states in the flat topological bands of moiré graphene, and optical studies of various types of excitons in the monolayer semiconductors.  1080 Physics Research Building America/New_York public

Dr. Minhao He

Princeton University

Visualizing and engineering quantum states of matter in vdW materials

Location: 1080 Physics Research Building

Faculty Host: Fengyuan Yang

Abstract: The study of electronic interaction is pivotal to understanding strongly correlated states and their collective excitations. Isolated flat bands provide ideal settings for such investigations thanks to their simple band structure. They can be realized in vdW materials either under a strong magnetic field, forming Landau levels, or at zero magnetic field with presence of a large moiré superlattice. In this talk, I will first highlight the recent direct visualization of the Wigner crystal in the Landau level of Bernal-stacked bilayer graphene, using scanning tunneling microscopy (STM). I will discuss how STM, combined with atomically clean vdW devices, reveals the quantum nature of electrons and provides microscopic insights into their behavior. In the second part, I will talk about recent advances in flat-band engineering, using graphene-based moiré superlattices as a case study. I will demonstrate the wide tunability of these flat bands and the rich interplay of flavor symmetry breaking and topological properties in the resulting quantum states. Finally, I will conclude by highlighting new opportunities enabled by zero-field topological flat bands engineered in moiré vdW materials.

Bio: Dr. Minhao He is currently a Princeton Quantum Initiative postdoc fellow working with Prof. Ali Yazdani in the Department of physics at Princeton University. His current work focuses on using scanning tunneling microscopy to directly visualize and explore the interacting electronic states emergent in the atomically thin vdW devices. He received his Ph.D. in Physics from the University of Washington in 2022, under the supervision of Prof. Xiaodong Xu, where he worked on both transport measurements of strongly correlated states in the flat topological bands of moiré graphene, and optical studies of various types of excitons in the monolayer semiconductors.