  Single crystalline thin films of complex oxides show a rich variety of
functional properties such as ferroelectricity, piezoelectricity, ferro and
antiferromagnetism etc. that have the potential for completely new electronic
applications (1-2). Direct synthesis of such oxides on Si remains challenging
due to the fundamental crystal chemistry and mechanical incompatibility of
dissimilar interfaces (3-16). Here we report integration of thin (down to 1
unit cell) single crystalline, complex oxide films onto Si substrates, by
epitaxial transfer at room temperature. In a field effect transistor using a
transferred Pb0.2Zr0.8TiO3 (PZT) layer as the gate insulator, we demonstrate
direct reversible control of the semiconductor channel charge with polarization
state. These results represent the realization of long pursued but yet to be
demonstrated single crystal functional oxides on-demand on silicon.
