Memristive Dynamics as a Device‐Level Probe for Metal Cation‐Molecule Binding Interactions

Peptide‐based memristive junctions present a promising route to integrate electronic functionality with biomolecular specificity; however, the potential of ion‐selective interactions to chemically program memristive dynamics and, conversely, to reveal molecular interactions through their electrical relaxation remain underexplored. Here, we demonstrate that metal cation identity can program the temporal conductance response of molecular junctions formed from a self‐assembled peptide monolayer. Using in situ electrical measurements under pulsed bias, we systematically compare eight cations and show distinct ion‐dependent relaxation behaviors: monovalent ions exhibit faster relaxation, whereas multivalent ions produce slower relaxation and greater history‐dependent conductance retention. Although the initial conductance response varies with ion concentration, the subsequent relaxation dynamics show no systematic concentration dependence within the investigated range, highlighting ion identity as a key determinant of the temporal response. Comparative site‐resolved calculations of ion–peptide binding energies further support an association between stronger ion–peptide binding interactions and longer relaxation times, providing a molecular‐level support for interpreting the electrical dynamics. Together, these results establish ion–peptide interactions as a means of chemically programming peptide memristors, extending molecular memory beyond programming conductance levels to programming their time‐dependent evolution, while demonstrating memristive relaxation as a device‐level probe of metal cation–molecule binding interactions.