Phase Sensitive Probes for Unconventional Superconductors

Abstract:

Phase-sensitive probes are essential tools for identifying pairing symmetries in unconventional superconductors. In this talk, I will present our studies on Josephson effect of unconventional superconductors. Particularly, I will introduce monopole superconductors, a class of topological superconductors with topology-enforced pairing nodes and discuss designs of Josephson junctions to distinguish monopole superconductors from other trivial or topological superconductors such as chiral superconductors. Additionally, I will also discuss multigranular superconducting rings with frustrated Josephson couplings, where we demonstrate that rings composed of chiral superconductors cannot spontaneously trap a π-flux. Following our analysis, we propose that β-Bi2Pd hosts a pairing, akin to helical equal-spin pairing, based on recent report of recent experimental observation of half-quantum flux in Little-Parks oscillation measurements.

 

References:

[1] JYZ, and Y. Li, Spontaneous flux trapping in multigranular rings of unconventional superconductors, to be posted soon.

[2] G. Frazier, J. Zhang, JYZ, X. Sun, and Y. Li, Designing Phase Sensitive Probes of Monopole Superconducting Order, PRResearch, 6, 043189 (2024).

[3] Y. Li, and F. D. M. Haldane, Topological Nodal Cooper Pairing in Doped Weyl Metals, PRL, 120, 067003 (2018).

 

 

Biography:

Junyi Zhang (张骏祎), Department of Physics and Astronomy, Johns Hopkins University

 

Junyi Zhang obtained his Ph.D. from Princeton University in 2021. He then joined Johns Hopkins University as a postdoctoral research fellow at the Institute for Quantum Matter. His research spans topological and correlated materials, magnetism, and atomic optical physics, with applications in quantum simulation and quantum information.