Nonvolatile reconfigurable sequential logic in a HfO2 resistive random access memory array. 
Resistive random access memory (RRAM) based reconfigurable logic provides a temporal programmable dimension to realize Boolean logic functions and is regarded as a promising route to build non-von Neumann computing architecture.  In this work, a reconfigurable operation method is proposed to perform nonvolatile sequential logic in a HfO2-based RRAM array.  Eight kinds of Boolean logic functions can be implemented within the same hardware fabrics.  During the logic computing processes, the RRAM devices in an array are flexibly configured in a bipolar or complementary structure.  The validity was demonstrated by experimentally implemented NAND and XOR logic functions and a theoretically designed 1-bit full adder.  With the trade-off between temporal and spatial computing complexity, our method makes better use of limited computing resources, thus provides an attractive scheme for the construction of logic-in-memory systems.