Dynamic Response of Silver Monolayers Adsorbed on Gold(100) upon an Oscillatory Variation of the Chemical Potential: a Monte Carlo Simulation Study

Abstract

On the basis that the underpotential electrochemical deposition of Ag atoms on the Au(100) surface exhibits sharp first-order phase transitions at well-defined values of the (coexistence) chemical potential (μcoex), we performed extensive simulations aimed at investigating the hysteretic dynamic behavior of the system close to coexistence upon the application of a periodic signal of the form μ(t) = μcoex + μo sin(2Πt/τ), where μo and τ are the amplitude and the period of the sweep, respectively. For relatively short periods and small enough amplitudes, the system becomes trapped either at low or high Ag coverage states, as shown by recording hysteresis loops. This scenario is identified as dynamically ordered states (DOS) such that the relaxation time (τrelax) of the corresponding metastable state obeys τrelax > τ. On the other hand, by properly increasing μo and/or τ, one finds that the Ag coverage gently follows the external drive (here τrelax < τ) and the system is said to enter into dynamically disord...