Nanowerk  May 7, 2024 It is shown that structural disorder in the form of anisotropic, picoscale atomic displacements modulates the refractive index tensor and results in the giant optical anisotropy observed in BaTiS3. An international team of researchers (University of Southern California, Washington University, University of Wisconsin–Madison, UC Santa Barbara, Lawrence Berkeley National Laboratory, Oak Ridge National Laboratory, Switzerland) used scanning transmission electron microscopy to directly observe the globally disordered Ti a–b plane displacements and found them to be ordered locally over a few unit cells. First-principles calculations showed that the Ti a–b plane displacements selectively reduced the refractive index […]