  The experimentally observed, ambipolar field-effect characteristics of Mott
insulators are reproduced in the one-dimensional Hubbard model attached to a
tight-binding model for source and drain electrodes. The formation of Schottky
barriers, originating from the work-function difference, is taken into account
by a potential satisfying the Poisson equation with an appropriate boundary
condition. Then, these field-effect characteristics are shown to be related by
unique current-voltage characteristics of metal-Mott-insulator interfaces.
