Degree of locality of elasto-optic response in solids
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2019-12-10 |
| Journal | Physical review. B./Physical review. B |
| Authors | Xin Liang, Sohrab IsmailāBeigi |
| Institutions | Yale University |
| Citations | 5 |
Abstract
Section titled āAbstractāThe elasto-optic effect, or photoelasticity, describes the linear change of dielectric tensor with applied strain and is a universal material property of insulators and semiconductors. Though the elasto-optic responses for solids can be computed directly from first principles (e.g., by using density functional perturbation theory) and measured experimentally, these methods do not provide sufficient insight into the governing microscopic physical principles of photoelasticity. In this work, we describe a microscopic first-principles analysis of photoelasticity in real space and apply it to investigate the elasto-optic responses of Si, diamond, NaCl, and MgO. By writing the random phase approximation (RPA) dielectric constant in the basis of maximally localized Wannier functions, we show that the strain-dependent change of dipole transitions between occupied and unoccupied Wannier functions are the main determinants of photoelasticity. By organizing the dipole transitions into spatially localized shells, we develop a āconstrained sumā method that converges both the dielectric and photoelastic responses systematically and reveals a relatively long-ranged nature to these responses: one needs to sum up contributions of up to third neighbor shells to converge the elasto-optic coefficient with reasonable precision.