Electron paramagnetic resonance study of the solid solutions Ru(S _1-xSe_x)₂

The method of electron paramagnetic resonance (EPR) has been used to study the n-type semiconducting Ru(S_1-xSe_x)₂ single crystals grown by the method of chemical vapor transport. A chalcogen point defect model is established to account for the S=1/2 paramagnetic species detected by EPR. This model assumes that an X^2-(X=S or Se)-X vacancy pair behaves like an electron donor. The g-factor anisotropy is dependent upon the degree of chalcogen deficiency which is interpreted as due to the formation of a narrow band by the magnetic electrons of the chalcogen defect below the bottom of the conduction band.