Calculated split-off energy (Δ_l) (l = 1, 2) of (La_0.5Bi_0.5O)CuCh (Ch = S, Se, Te) systems.

System	Split-off energy (Δl) (in meV)		δ 12 = Δ1 − Δ2
	Δ 1 (Z point)	Δ 2 (Γ point)
(La0.5Bi0.5O)CuS	350	349	1
(La0.5Bi0.5O)CuSe	586	569	17
(La0.5Bi0.5O)CuTe	897	841	56