Piezomodulation of excitonic reflectance spectra in CuCl

We have investigated the piezoreflectance spectra of the 1s Z3 and Z12 excitons in single crystals of copper chloride CuCl at 95 K with linearly polarized light. The spectra were studied for the applied low pressure p (p lower than 1 MPa) directed along the [001], [111] and [110] axis with the wave vector k of the incident light parallel to the [1 ¯ 10] direction. A strong piezo-optical response is observed for the Z3 exciton to regard to the one observed for Z12. From the stress-induced shifts and splitting of the excitonic levels, we have been able to deduce the shear excitonic deformation potentials: b = (−0.18±0.02) eV and d = (0.30±0.03) eV. C 2005 Springer Science + Business Media, Inc.