Semiconductor ferromagnetism in quantum dot array

Ferromagnetism is theoretically predicted in non-magnetic semiconductor-dot arrays. We propose two types of bipartite dot-arrays which show flat-band ferromagnetism according to the Lieb theorem. We verify spin-polarized grou nd states at half-filling by performing an exact diagonalization calculatio n. The ferromagnetic states can be fi eely switched on and off by changing the electron-filling via the gate voltage.