Anomalous Exciton Spectra in Uniaxially Deformed CuCl: Experimental Evidence for the Effect of the Stress-Inducedk-Linear Term

Anomalous exciton spectra have been observed in uniaxially deformed CuCl. The observed features, which cannot be accounted for by the previous theory, were successfully interpreted by the effect of the stress-induced $k$-linear terms in the energy band of CuCl, as very recently proposed by Sakoda and Onodera. Experimental evidences for this interpretation are presented.