Incommensurate charge density wave modulated by period of Hubbard superlattices

The charge structure factor of the half-filled Hubbard superlattices with one on-site repulsive site and L-0 free sites per unit cell is investigated numerically. The behaviors of charge structure reveal a kind of evenodd L-0 disparity. For even L-0, we always observe a commensurate charge density wave (CDW). For odd L-0, we observe a commensurateincommensurate CDW transition at a critical on-site repulsion around the particlehole symmetric point. This transition results from the competition between the local charge correlations with odd distance and even distance.