GROUND-STATE PROPERTIES OF SOLID-ON-SOLID MODELS WITH DISORDERED SUBSTRATES

We study the glassy superrough phase of a class of solid-on-solid mode ls with a disordered substrate in the limit of vanishing temperature b y means of exact ground states, which we determine with a minimum-cost -flow algorithm. Results for the height-height correlation function ar e compared with analytical and numerical predictions. The domain-wall energy of a boundary-induced step grows logarithmically with system si ze, indicating the marginal stability of the ground state, and the fra ctal dimension of the step is estimated. The sensibility of the ground state with respect to infinitesimal variations of the quenched disord er is analyzed.