Piezooptical studies of group 4B transition metal disulfides ZrS 2 and HfS2

Article abstract of DOI:10.1143/JPSJ.60.1814

Piezotransmission spectra near the indirect absorption edge and piezoreflectance spectra in the visible region of group 4B transition metal disulfides ZrS₂ and HfS₂ have been studied by the stress modulation technique at 77 K. The uniaxial stress X was applied along the a axis and the spectra were measured using the polarized light, E//X and E⊥X, where E is the electric field of the incident light. The change of the energy levels by the strain is evaluated by comparing the piezo-modulated spectra with the wavelength-modulated spectra. The main peak and the broad structure at higher energy side in the spectra originate from the overlapping of the transitions at and near T point and the other structures at lower energy side are due to the transitions at L and M points.