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Ayumi Fujita

Publications and source records attributed to Ayumi Fujita.

2 recordsLinked to original sources

Vortex dissipation and level dynamics for the layered superconductors with impurities

We study parametric level statistics of the discretized excitation spectra inside a moving vortex core in layered superconductors with impurities. The universal conductivity is evaluated numerically for the various values of rescaled vortex velocities $κ$ from the clean case to the dirty limit case. The random matrix theoretical prediction is verified numerically in the large $κ$ regime. On the contrary in the low velocity regime, we observe $σ_{xx} \propto κ^{2/3}$ which is consistent with the theoretical result for the super-clean case, where the energy dissipation is due to the Landau-Zener transition which takes place at the points called ``avoided crossing''.

cond-mat.supr-con↗

Langevin Simulation of Nonlocal Ginzburg-Landau Model for Superconductors in a Magnetic Field

We numerically investigate the phenomenological nonlocal Ginzburg-Landau Hamiltonian for two-dimensional superconductors in a strong magnetic field by Langevin equation. We obtain a regular vortex lattice which is very near to the square lattice. We calculate the structure factor and Abrikosov factor at various temperatures. We also evaluate the specific heat and obtain a cusp which indicates the melting of the vortex lattice.

cond-mat.supr-con↗