Searcharxiv⌕ Search

arXiv subjects

Jefferson Tang

Publications and source records attributed to Jefferson Tang.

2 recordsLinked to original sources
arXiv2025

Probing Pair Density Waves with Twisted Josephson Junctions

We show that twisted interfaces between superconductors can serve as a phase-sensitive platform for the detection and characterization of pair density waves (PDW). In the presence of an in-plane magnetic field, the critical Josephson current of a twisted PDW interface is maximal at a finite field value, determined by the twist angle and the PDW period -- an explicit signature of the PDW. The results are robust to variations in junction geometry and can be adapted to certain cases with strong disorder or fluctuations. Their temperature dependence allows to distinguish pure PDW from byproducts of coexistence of superconductivity and charge- or spin- density waves.

cond-mat.supr-con↗
arXiv2025

Dynamical signatures and control of time-reversal breaking in twisted nodal superconductors

Recent observations of time-reversal breaking superconductivity at twisted cuprate interfaces motivate the development of new approaches to better characterize this emergent phenomenon. Here we study the dynamical properties of the order parameters at the twisted unconventional superconductor interfaces. We reveal the emergence of a soft collective mode (Josephson plasmon) at the time-reversal breaking transition, which can be tuned by temperature, twist angle or magnetic field. Furthermore, nonlinear dynamical responses contain direct signatures of both the transition and the broken symmetry itself. In particular, we show that the generation of a second harmonic voltage under alternating current driving is a necessary and sufficient signature of time-reversal symmetry breaking. Finally, we demonstrate that strong nonlinear driving induces dynamical phase transitions between phases with and without spontaneous symmetry breaking, introducing a tool for their out-of-equilibrium control. We discuss the signatures of our predictions in AC current-driven experiments on twisted Bi$_2$Sr$_2$CaCu$_2$O$_{8+x}$ interfaces.

cond-mat.supr-con↗