Multiscale phenomena in materials are notoriously difficult to model because they elude conventional techniques like molecular dynamics and continuum mechanics. This is a problem because most interesting phenomena do in fact span multiple orders of magnitude in terms of time and length scales. For example, the electronic properties of perovskites, which are of extraordinary interest due to applications ranging from extremely high efficiency solar cells to light-emitting diodes, are determined by atomic scale microstructure. However, perovskite processing, which determines the microstructure, is on the time scale of diffusion. Consequently, new techniques are necessary.

Eli works on developing the phase-field crystal (PFC) method, a promising new modeling framework for tackling such problems. Rather than considering point particles, the system tracks a smooth atomic density field, which is the average of atomic positions on short-time scales. Subsequently, the system is evolved by solving a partial differential equation, which decreases the free energy.

**Publications:**

**E. Alster**, K.R. Elder, J.J. Hoyt, and P.W. Voorhees, “Phase-field-crystal model for ordered crystals.”*Phys. Rev. E***95**, 022105 (2017). https://doi.org/10.1103/PhysRevE.95.022105