First-principles study of electronic and optical properties of ternary compounds AuBX2 (X = S, Se, Te) and AuMTe2 (M = Al, In, Ga)

The structural, electronic and optical properties of AuBX2 (X = S, Se, Te) and AuMTe2 (M = Al, Ga, In) crystals with a chalcopyrite structure were investigated using first principles projector augmented wave (PAW) method with the PBE-GGA functional and the modified Becke-Johnson (mBJ) potential including spin-orbit coupling (SOC) effects. The results show finite band gaps in all the compounds with mBJ and SOC. AuBS2 and AuBSe2 are found to have indirect band gaps, and the tellurides are effective direct band-gap semiconductors. The calculated optical quantites using mBJ and SOC show low energy loss and reflectivity, and high absorption capability in the infrared and visible regions for AuBX2 (X = S, Se, Te) and AuAlTe2, which suggest potentials of using these compounds for solar cell applications.

Automated summary

The study found that AuBX2 and AuMTe2 crystals have finite band gaps under mBJ and SOC, with some compounds having indirect band gaps and tellurides being direct band-gap semiconductors. Calculated optical properties show these compounds have low energy loss and reflectivity, as well as high absorption capability in the infrared and visible regions, suggesting potential for solar cell applications.