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arXiv · 2401.07397

Picosecond Trajectory of Two-dimensional Vortex Motion in FeSe$_{0.5}$Te$_{0.5}$ Visualized by Terahertz Second Harmonic Generation

Sachiko Nakamura·Haruki Matsumoto·Hiroki Ogawa·Tomoki Kobayashi·Fuyuki Nabeshima·Atsutaka Maeda·Ryo Shimano
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Abstract

We have investigated the vortex dynamics in a thin film of an iron-based superconductor FeSe$_{0.5}$Te$_{0.5}$ by observing second-harmonic generation (SHG) in the THz frequency range. We visualized the picosecond trajectory of two-dimensional vortex motion in a pinning potential tilted by Meissner shielding current. The SHG perpendicular to the driving field is observed, corresponding to the nonreciprocal nonlinear Hall effect under the current-induced inversion symmetry breaking, whereas the linear Hall effect is negligible. The estimated vortex mass, as light as a bare electron, suggests that the vortex core moves independently from quasiparticles at such a high frequency and large velocity $\approx$300 km/s.

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Sachiko Nakamura, Haruki Matsumoto, Hiroki Ogawa, Tomoki Kobayashi, Fuyuki Nabeshima, Atsutaka Maeda, Ryo Shimano. 2024-01-15. Picosecond Trajectory of Two-dimensional Vortex Motion in FeSe$_{0.5}$Te$_{0.5}$ Visualized by Terahertz Second Harmonic Generation. https://doi.org/10.1103/physrevlett.133.036004

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