Events on Thursday, December 12th, 2024
- Topology and phase transitions in twisted nodal superconductors and beyond
- Time: 10:00 am - 6:00 pm
- Place: 5310 Chamberlin
- Speaker: Pavel Volkov, University of Connecticut
- Abstract: “Twistronics” paradigm has been tremendously successful in realizing strongly correlated and topological phases of electrons in two-dimensional semiconductors or semimetals. In my talk, I will show that twisted bilayers of nodal superconductors allow a similar degree of control over the neutral quasiparticles in superconductors. I will demonstrate that the spectrum of the superconducting Dirac quasiparticles close to the gap nodes is strongly renormalized by twisting and can be further controlled externally. In particular, the application of an interlayer current transforms the system into a topological superconductor at any nonzero twist angle, while magnetic field can be used to create periodic lattices of alternating Chern domains [1]. Moreover, at large twist angles near 45°, frustrated Josephson coupling can drive spontaneous time-reversal breaking. A promising platform to observe these effects is provided by the high-Tc cuprates, and I will discuss the theoretical description of the experimental results on twisted flakes of Bi2Sr2CaCu2O8+x [2]. Moving on from superconductors, I will discuss the ongoing work on elucidating more broadly the role of symmetries in moire materials, with the example of realization of t-t’-U Hubbard models in twisted square lattice materials [3]. [1] P. A. Volkov, K. P. Lucht, J. H. Wilson and J. H. Pixley, Physical Review Letters 130, 186001 (2023) [2] S. Y. F. Zhao, X. Cui, P. A. Volkov, …, P. Kim, Science 382, 6677, 1422 (2023). [3] P. M. Eugenio, Z-X Luo, A. Vishwanath, P. A. Volkov, arXiv:2406.02448 You can also get more information on Pavel's website pavolkov.com
- Host: Ilya Esterlis