Atomistic Origins of Molecular Memristors

Memristive conductance switching has been observed recently in molecular junctions, offering another instance of the newly discovered electronic device, the memristor, and a gamut of novel possibilities to the microelectronics industry. However, the underlying mechanism of this type of switching is not well understood, with current debate centering on whether the molecule “or” the metal−molecule interface is responsible for the switching. Here, we pinpoint the atomistic origin of the switching and demonstrate that it arises from electronic and ionic changes at the metal−molecule interface. The role of the molecule is important, however, in determining the geometrical arrangement of the interface and thus its electronic properties. Understanding the memristive-switching mechanism in these devices allows the design and engineering of target molecules, necessary to achieve the full promise of nonvolatile memory devices.