We have investigated various TiN/MgO-1x1, 2x1, 2x2, and 3x3 superlattices[1][2][3] using the total energy pseudopotential[4][5] method. The electronic states of TiN/MgO-1x1 and -2x1 superlattices are metallic. In contrast, the rectangular TiN dot/MgO-2x2 and -3x3 superlattices correspond to semiconductor although the electronic states of the rectangular parallelepiped TiN dot/MgO-2x2 and -3x3 superlattices are metallic. A nonmetallic state is more suitable to enhance thermoelectric properties. The band gap values of the rectangular TiN dot/MgO-2x2 and -3x3 superlattices are 0.18 and 0.54 eV[2] in the DFT-LDA[6][7][8] calculation, respectively. It will be expected larger band gap values in TiN dot/MgO-4x4 superlattices. We calculate the rectangular and rectangular parallelepiped TiN dot/