A magneto‐reflectivity study of CuGaSe2 single crystals

CuGaSe2 single crystals are studied using magneto-reflectivity at 4.2 K in magnetic fields B up to 20 T. The A and B free excitons, observed in the optical reflectivity spectra, blue shift with increasing B. A low-field perturbation approach within the anisotropic hydrogenic model is used to fit the dependence of the spectral position of these excitons on B. The A and B exciton reduced masses of 0.115m0 and 0.108m0 (m0 is the free electron mass), Rydbergs of 12.9 and 12.2meV, Bohr radii 5.08 and 5.4 nm, and effective hole masses of 0.64m0 and 0.48m0, respectively, are determined.