Examining the screening limit of field effect devices via the metal-insulator transition

The electronic screening length, the distance over which an electric field is attenuated in a material, imposes a lower physical bound on the lateral size scaling of semiconductor field effect devices. Alternatives will be needed to achieve devices whose characteristic dimensions approach a nanometer. In this work, we demonstrate the atomic-scale nature of screening at high electron densities, using the polarization field of a ferroelectric oxide, Pb ( Zr , Ti ) O 3 , to electrostatically modulate the metallicity of ultrathin manganite La 1 − x Sr x Mn O 3 (LSMO) films near the metal-insulator transition. Within the screening length, the transport characteristics of LSMO vary sharply at the scale of a single atomic layer.