Contributions of Correlated Acentric Atomic Displacements to the Nonlinear Second Harmonic Generation and Response

High Resolution Image Download MS PowerPoint Slide Group theory and ab initio electronic structure calculations are combined to formulate a general protocol called “SAFOR” to understand and predict how to improve the second harmonic generation (SHG) response in acentric nonlinear optical crystals. Using the prototypical SHG borate β-BaB 2 O 4, we show how the SHG d -tensor can be formulated from mode effective d ij coefficients obtained as a linear combination of symmetry-adapted displacement patterns that transform as irreducible representations of a centrosymmetric parent structure. Since this protocol does not require any constraints on the crystal topology or anionic moieties in the structure, we suggest it constitutes a powerful tool to understand and design new SHG compounds through atomic-structure governing principles.