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 0.115 m0 and 0.108 m0 (m0 is the free electron mass), Rydbergs of 12.9 and 12.2 meV, Bohr radii 5.08 and 5.4 nm, and effective hole masses of 0.64m0 and 0.48 m0, respectively, are determined. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.The crystal growth was supported by the FASO of Russia (“Quantum” No 01201463332), the magneto-optical study was supported by the Russian Science Foundation (grant 17-12-01500) and LNCMI-CNRS (EMFL)