Piezoreflectivity of Potassium Chloride at about 12 eV

Abstract

Piezoreflectivity spectra of KCl are studied by using a uniaxial stress along the [011] direction at room temperature. Two structures are newly observed at about 11.5 and 12.3 eV. In this energy range, a broad reflection band identified with transitions to the second and third lowest conduction bands is known to be located. Trigonal deformation potentials of the two structures are found to be −0.18±0.12 and 0.14±0.07 eV, respectively. From a comparison of these deformation potentials with those of the exciton at the absorption edge and of the core exciton at about 20 eV, it is concluded that the second and third lowest conduction bands are of the dγ and dε symmetry.