Uniaxial-stress dependence of the first-order Raman spectrum of rutile. I. Experiments

We report an investigation of the uniaxial-stress dependence of the first-order Raman spectrum of rutile (TiO2). We find a normal-mode behavior, characterized by an increase in the phonon frequency versus uniaxial compression, for the two Raman modes 1 (A1g) and 5 (Eg). We deduce two deformation potentials for 1 (in unit of cm-1): a1=-610 cm-1, b1=-820 cm-1 and four deformation potentials for 5 (doubly degenerate mode): a5=-1170 cm-1, b5=-1840 cm-1, c5=+35 cm-1, and d5=-230 cm-1. We find less classical results for 3 (B1g): the phonon frequency increases for uniaxial stress parallel to c but decreases for uniaxial stress parallel to a ([100] direction) or parallel to a ([110] direction). The corresponding deformation potentials are a3=+620 cm-1 and b3=+330 cm-1. Within experimental error, all phonon energies displace linearly versus deformation. © 1980 The American Physical Society.