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2D structures (surface particles)

Particles deposited on or suspended from a surface or interface. The structure defines how scattering from multiple particles combines.

For dilute distributions, particles scatter independently. For ordered or partially ordered systems, the structure also describes spatial correlations.

Positioning: deposit vs suspend

2D structures can be positioned in two ways:

  • Deposit: The bottom of particles is placed at the layer’s bottom interface. Use deposit2D or addDeposit2D. Appropriate for particles sitting on a substrate.
  • Suspend: The top of particles is placed at the layer’s top interface. Use suspend2D or addSuspend2D. Appropriate for particles hanging from below an interface, such as holes or inclusions embedded in a substrate.

For other vertical positions, translate the particle before constructing the 2D structure.

Disordered particles

For uncorrelated particles on a surface:

structure = ba.Dilute2D(density, particle)
layer.deposit2D(structure)

Ordered structures

For particles with spatial correlations, use structured layouts:

structure = ba.Crystal2D(particle, lattice)
layer.deposit2D(structure)

Structure types include:

  • 1D/2D crystal: particles at periodic positions
  • Paracrystal: short-range order with cumulative disorder