Effect of external noise on the transport property of two-band tight-binding superlattices

Within a two-band tight-binding model driven by a dc-ac electric field, we investigate the effect of external noise on the transport property of electrons in superlattices. We find that external noise can destroy the periodicity of the transient current and cancel the long-time average current peaks. The magnitude of the noise is usually in the order of ten percent of E₀ (static electric field), which affects the transient and averaged currents strongly. Increasing the noise strength, the height of the current peaks decreases, and the width increases. A similar change appears while we increase the decay constant of the noise.