We are developing phase-field models based on the Ginzburg-Landau theory for the dynamics as well as spatial and temporal variations of the applied magnetic field of a typical type II superconductor with arbitrary geometry. It is being parameterized by first-principles calculations of the key parameters describing the spatial/topological characteristics of the quantum states, as well as the influence of strain on these states, focusing on understanding superconductivity in Se-deficient α-FeSe_1–x and FeSe_xTe_1–x thin films. The computational predictions will be validated by growing FeSe samples grown on SrTiO₃ substrate.

(a) ψ*ψ, supercurrent density, and (b) magnetic field strength in the superconductor during the time evolution of the system. Two vortices of opposite orientation can be seen annihilating each other, as well as a vortex with more than one quantum of magnetic flux splitting into multiple vortices.