Writing and erasing information in multilevel logic systems of a single molecule using scanning tunneling microscope

Large double negative differential resistance (NDR) has enabled a single quinone derivative to be stable in the neutral (0), singly reduced (1), typical neutral conformation generated by releasing the charge (2), and doubly reduced state (3) at 90 K. The authors wrote and erased information by switching a single molecule among these four conducting states (0,1,2,3) showing random access memory and read only memory applications for terabit memory generation in future. Origin of NDR is investigated in typical functional groups of the molecule, in local environment, and at atomic junction with scanning-tunneling-microscope tip to conclude NDR as a collective phenomenon. (c) 2006 American Institute of Physics.