Delta E 1 ( g ) and Delta E 2 ( h ) along the (Gamma-bar)-(M-bar) direction at k z = 0.28 c * by increasing the value of ∑ q i from 0 to 0.52 eV, where the ratio q 1 : q 2 + q 3 : q 4 is fixed. The black curve corresponds to the best fit to DFT ( b ).
