Voltage induced conformational changes and current control in charge transfer through molecules

Transport through molecular contacts with a sluggish intramolecular vibrational mode strongly coupled to excess charges is studied far from equilibrium. A Born-Oppenheimer approximation in steady state reveals voltage dependent energy surfaces which cause abrupt conformational changes of the molecular backbone. These are directly related to transitions between current plateaus which are relatively robust against thermal fluctuations and appear in patterns reminiscent of Coulomb diamonds. In a regime accessible in experiments bias and gate voltages allow for an efficient control of charge transfer or may trigger a molecular rotor.