Embodiments of the invention provide a multi-terminal resistance device
with first and second electrodes, a shared third electrode, and a
resistance layer providing first and second current paths between the
shared third electrode and the first and second electrodes, respectively.
A current state of the device may be programmed by applying one or more
electrical signals along the first and/or second current paths to change
a resistance of the device. In some embodiments, applying an electrical
signal may switch a junction resistance of the first and/or second
electrodes and the resistance layer between two or more resistance
values. The device may include a shared fourth electrode to provide extra
programming capability. In some embodiments, the device may be used to
store a data state, to determine a count of multiple electrical signals,
or to perform a logic operation between two electrical signals.