Anomalous behavior of critical current in a superconducting film triggered by DC plus terahertz current

Anomalous behavior of critical current in a superconducting film triggered by DC plus terahertz current

Blog Article

Abstract The critical current in a superconductor (SC) determines the performance of many SC devices, including SC diodes which have attracted recent attention.Hitherto, studies of SC diodes are limited in the DC-field measurements, and their performance under a high-frequency current remains unexplored.Here, we conduct the first investigation on the interaction between the DC and terahertz (THz) current in a SC artificial superlattice.

We found that the DC critical current is sensitively modified by THz pulse excitations in a nontrivial manner.In particular, at low-frequency THz excitations below the SC LED Voltmeter gap, the critical current becomes sensitive to the THz-field polarization direction.Furthermore, we observed anomalous behavior in which a supercurrent flows with an amplitude larger than the modified critical current.

Assuming that vortex depinning determines the critical current, we show Microwave / Oven Globe that the THz-current-driven vortex dynamics reproduce the observed behavior.While the delicate nonreciprocity in the critical current is obscured by the THz pulse excitations, the interplay between the DC and THz current causes a non-monotonic SC/normal-state switching with current amplitude, which can pave a pathway to developing SC devices with novel functionalities.