Tunable Competing Orders in Van Hove Metals: Case Studies of Few-Layer van der Waals Systems, Prof. Yi-Ting Hsu, University of Notre Dame
R124
Few-layer van der Waals materials offer a versatile platform to investigate correlated quantum phases. A central theme in both twisted and untwisted graphene and transition metal dichalcogenides systems is the emergence of Van Hove singularities (VHS), which strongly enhance electronic interactions and can drive competing orders.
In this talk, I will discuss how few-layer van der Waals systems near the Van Hove filling can be generally described by a Van Hove Metal, where the symmetry-broken and topological phases arise solely from intra- and inter-VHS interactions within a renormalization group framework, largely independent of the Fermi surface details. I will show that by tuning the number and type of VHS—through spin-orbit coupling, external fields, or twist angle—one can engineer controlled competition among orders. I will illustrate this mechanism through two case studies: twisted bilayer WSe2 and Bernal bilayer graphene proximitized by WSe2, and discuss experimental probes that can test these predictions. Our findings highlight Van Hove fermiology as a general strategy to design and control exotic phases in two-dimensional quantum materials.
References:
[1] YTH, Wu, Das Sarma, Phys. Rev. B 102, 085103 (2020). Editor’s suggestion.
[2] YTH, Wu, Das Sarma, Phys. Rev. B 104, 195134 (2021).
[3] Son, YTH, Kim, Phys. Rev. B 111, 115144 (2025). Editor’s suggestion.
[4] Yang and YTH, arXiv:2508.21119 (Accepted by Communications Physics)