[Jan.9] Physics Special Seminar - Dr. Youngjoon Choi (University of Ca…

물리학과에서는 특별세미나를 아래와 같이 개최하오니 관심있는 분들의 많은 참석을 바랍니다.

1. 연사: 최영준 박사 (University of California Santa Barbara)
2. 일시: 2025. 1. 9(목), 오후 4시
3. 장소: 공학3동 302호 (세미나실)

4. 제목: Electric field control of superconductivity and quantized anomalous Hall effects in rhombohedral tetralayer graphene

Inducing superconducting correlations in chiral edge states is predicted to generate topologically protected modes with exotic quantum statistics. Past experimental efforts have focused on engineering interfaces between superconducting materials and quantum Hall systems. We present rhombohedral tetralayer graphene as an ideal platform for these hybrid interfaces leveraging the gate-tuned ground states between intrinsic superconductors and quantum anomalous Hall states. We find multiple superconducting states, including one phase with critical temperature Tc = 55mK at superlattice filling ν≈ −3.5 for layer polarization corresponding to a weak moire potential. Quantized anomalous Hall effect occurs at ν = −1 for weak moire potential, with a measured Chern number |C| = 4. Remarkably, gate voltage can also trigger nonvolatile switching of chirality in the quantum anomalous Hall state, enabling reconfiguration of topological edge mode networks in devices with local gate. We also find fractional and integer Chern insulators at zero magnetic field via thermodynamic compressibility measurements at ν = +2/3 and +1. These findings open new possibilities for hybrid interfaces between superconductors and topological edge states in the low-disorder limit.