EQMResearch group
Level 6 · Putting it together

From spin pattern to reflectance dip

Spins → magnetic phases → per-layer dielectric → TMM → reflectance. Walk the pipeline once and the rest of the app becomes obvious.

Build on:Spin pattern,Phase window (3-cell rule),Transfer-matrix method (TMM),Reflectance spectrum R(E)

The whole pipeline in one breath

Every time you flip a single spin in the simulator, the following chain of events fires off in the backend:

Spin array0/1 per layerPhase ruleAFM / Mixed / FMε(E) mapLorentz per phaseTMM1D wave solverR(E)your spectrumFrom the spin pattern on the left to the reflectance dip on the rightEditing one spin re-runs every box to its right.

Block by block

  1. Spin array. The 0/1 list of arrows you sketched in the editor (page).
  2. Phase rule. A 3-cell sliding window classifies each layer as AFM, Mixed or FM (page).
  3. ε(E) map. Each phase comes with its own Lorentz oscillator parameters; we build a per-layer dielectric function and from it the per-layer refractive index.
  4. TMM. The whole stack (Au, CrSBr, DBR, substrate) is fed into the transfer-matrix method at every photon energy in the chosen window.
  5. R(E). Out comes the reflectance spectrum — the dip moves, the polariton appears, and you start over.
Key takeaways
  • Five steps from a flipped arrow to a moved dip.
  • The bottleneck is TMM at hundreds of energies; everything else is cheap.
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