Physics Club - Eli Zeldov - Weizmann Institute of Science

Seeing Broken Symmetries: Chiral Superconductivity in Graphene Chiral superconductivity is a long-sought quantum state that spontaneously breaks time-reversal symmetry and has been predicted to host exotic topological excitations with potential applications in quantum information. Despite decades of theoretical and experimental effort, direct thermodynamic evidence for this elusive phase has remained absent. In this talk, I will show how nanoscale magnetic imaging can reveal broken symmetries in quantum materials [1], focusing on rhombohedral graphene, a recently discovered platform for strongly correlated electronic phases and unconventional superconductivity [2]. Using nanoscale SQUID-on-tip magnetometry, we directly image the spontaneous breaking of time-reversal symmetry in the superconducting state, providing the first thermodynamic evidence for chiral superconductivity [3]. The measurements further reveal that the chiral superconducting domains emerge from an underlying spin–valley isospin-polarized parent state, uncovering an intimate connection between symmetry breaking in the normal and superconducting phases. Beyond establishing chiral superconductivity, we demonstrate deterministic electrical control of chiral domains with ultralow currents, enabling reversible switching between superconducting states of opposite chirality. These findings establish rhombohedral graphene as a unique platform for exploring topological superconductivity and illustrate how real-space magnetic imaging can reveal and control broken symmetries in strongly correlated quantum materials. [1] N. Auerbach, S. Dutta, M. Uzan, Y. Vituri, Y. Zhou, A.Y. Meltzer, S. Grover, T. Holder, P. Emanuel, M.E. Huber, Y. Myasoedov, K. Watanabe, T. Taniguchi, Y. Oreg, E. Berg, and E. Zeldov, Nat. Phys. 21, 1765 (2025). [2] T. Han, Z. Lu, Z. Hadjri, L. Shi, Z. Wu, W. Xu, Y. Yao, A. A. Cotten, O. Sharifi Sedeh, H. Weldeyesus, J. Yang, J. Seo, S. Ye, M. Zhou, H. Liu, G. Shi, Z. Hua, K. Watanabe, T. Taniguchi, P. Xiong, D. M. Zumbühl, L. Fu, and L. Ju, Nature 643, 654 (2025). [3] S. Dutta, N. Auerbach, T. Han, Y. Zhou, G. Shavit, N. S. Kander, Y. Myasoedov, M. E. Huber, K. Watanabe, T. Taniguchi, L. Ju, and E. Zeldov, arXiv:2605.13303. (This event will not have a livestream. However a recording will be made available)