Electronic structure of ternary thallium chalcogenide compounds

The electronic structures of the ternary thallium chalcogenide compounds, TIGaSe2 and TIGaS2 are studied, using the linear muffin-tin orbital (LMTO) method. The calculated band dispersion shows that both compounds are indirect gap semiconductors. For both compounds, the top of the valence bands is located at Gamma. For TIGaSe2, the bottom of the conduction band is located along the Z(0, 0, - 5) - L(0.5, 0.5, - 0.5) line. For TIGaS2, the bottom of the conduction band is located along the Gamma-Y(0, 1, 0) line. An inspection of the LMTO wave functions shows that the valence band top has the character of TI: 6s-Se: 4p or S:3p antibonding state, while the conduction band bottom has the character of TI:6p-Se:4p or S:3p antibonding state. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.