EQMResearch group
Level 5 · CrSBr & the experiment

Phase window (3-cell rule)

A sliding 3-layer window classifies each spot as AFM, Mixed, or FM. This is the bridge from raw spins to optical refractive indices.

Build on:Spin pattern,Ferromagnetism (FM),Antiferromagnetism (AFM),Mixed phase / domain wall

The 3-cell rule

The simulator turns each spin into a magnetic phase by looking at it together with its two immediate neighbors. The rule is embarrassingly simple:

  • All three spins identical → FM.
  • Strict ↑↓↑ or ↓↑↓ → AFM.
  • Anything else → Mixed.

That's exactly what the original Python helper spin_array_manual_v2 does — and what the JS port in lib/phases.ts mirrors so the editor can colour itself instantly without a backend round-trip.

See the window slide

Hover any cell below and the orange highlight shows the 3-layer window the classifier used to label it:

AFM 19Mixed 2FM 0Hover a cell to see the 3-layer classification window.
Key takeaways
  • 3-cell window decides the local phase.
  • Phase decides which Lorentz oscillator goes into the layer.
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