Driven Vortex Motion in Periodic Channel Potential Embedded in Superconducting Films

Abstract

In this paper, we investigate vortex dynamics in periodically width-modulated superconducting channels by numerically solving the time-dependent Ginzburg-Landau (TDGL) equations. The channels are designed with sinusoidally varying widths characterized by their average width and modulation amplitude. The motion of driven vortices generates an oscillatory electric field with a fundamental frequency, $f_0$, set by the channel periodicity, together with higher-order harmonics. In contrast to the situation of vortex lattice dynamics in a periodic pinning landscape of circular holes considered by Al Luhaibi et al. [1], we show that the harmonic content of the generated electric field can be effectively controlled through the channel geometry. In particular, appropriately engineered channel profiles strongly suppress higher-order harmonics, yielding an electric-field response that closely approaches a pure sinusoidal waveform. These results demonstrate that geometric modulation offers a viable route to engineering low-harmonicity microwave signals in superconducting devices and may enable cryogenic on-chip waveform generators for controlling superconducting qubits. Such devices could provide a useful building block for scalable transmon-based quantum computing architectures.