Phase-change material used to create single bits that act as multiple logic gates

Ars Technica : Phase-change materials take on different physical structures depending on the speed at which they are cooled. They are amorphous with a high electrical resistance when quickly cooled, and regular with low resistance when slowly cooled. The materials have been used to create computer memory bits, and last year they were combined with resistors to form logic gates . Now a group of researchers has created a single phase-change memory bit that can act as multiple logic gates. To do that, they provide a low level of heating to the hardware, which makes flipping the bit easier. Then they use pulses of low heat and high heat, representing 0 and 1 respectively, to affect how the bit functions. A single pulse causes the bit to behave as an OR gate, and combinations of pulses can cause it to behave as a NOR or NAND. The low-level heating increased the speed at which the bit switches states to nearly the same speed as modern processors. It is not yet clear whether having a single bit perform multiple gate functions will be useful, but the development is an important proof-of-concept step for phase-change materials in computing.