날짜 | 2024-02-16 10:00 |
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일시 | Feb.16th(Fri) 10:00AM |
장소 | E6, #1323 |
연사 | Hyeok-Jun Yang (Dep. of Physics, University of Notre Dame) |
In Van der Waals materials, the Van Hove singularity (VHS) enhances interaction effects and can drive a rich variety of collective orders and topological phases, including conventional and unconventional superconductivity. Although the diverging density of states and susceptibilities have been extensively studied, the VHS type such as the degree of divergence is often unclear in experiments. In this work, we theoretically show that the optical response in superconducting states can be used to experimentally infer the energy dispersion of relevant VHS. Our remark is that the current relaxation is related to the effective mass behavior so that the optical absorption intensity dramatically depends on the VHS type. Our study suggests the anisotropy of absorption spectra as a possible signature to distinguish and identify two types of VHS, conventional and higher-order VHS.