First-principles calculation of the structural, electronic, elastic, and optical properties of sulfur-doping <italic>ε</italic>-GaSe crystal

First-principles calculation of the structural, electronic, elastic, and optical properties of sulfur-doping ε-GaSe crystal

Huang Chang-Bao, Wu Hai-Xin^†,, Ni You-Bao, Wang Zhen-You, Qi Ming, Zhang Chun-Li

Refractive indexes of ε-GaSe, GaSe_0.75S_0.25, and β-GaS calculated by using the DFPT method. The phonon effects make the dispersion curves slope downward. From ε-GaSe to GaSe_0.75S_0.25 to β-GaS, the refractive index is decreasing and the birefringence is increasing.