Polarizability of shallow donors in EuSe

Permittivity measurements at a microwave frequency 24 GHz have been made on n-type EuSe at low temperatures 4.2–77 K after various annealing times. Consideration of different models for annealing dependent permittivity leads to the polarizability of Se vacancy defects as the most likely explanation. Donor polarizability $\text{α}{}_{\mathrm{d}}\text{= 3.2 × 10}{}^6\text{A}\text{?}{}^3$is found and further an estimation for electron effective mass $\text{m}{}^1\text{= 0.28m}{}_0$.