Virtually all digital devices that perform any sort of processing of information require not only a processing unit, but also a quick memory that can temporarily hold the inputs, partial results, and outputs of the operations performed. In computers, this memory is referred to as dynamic random-access memory, or DRAM. The speed of DRAM is very important and can have a significant impact in the overall speed of the system. In addition, lowering the energy consumption of memory devices has recently become a hot topic to achieve highly energy-efficient computing. Therefore, many studies have focused on testing out new memory technologies to surpass the performance of conventional DRAM.
The most basic unit in a memory chip are its memory cells. Each cell typically stores a single bit by adopting and holding one of two possible voltage values, which correspond to a stored value of either "0" or "1." The characteristics of the individual cell largely determine the performance of the overall memory chip. Simpler and smaller cells with high speed and low energy consumption would be ideal to take highly efficient computing to the next level.
A research team from Tokyo Tech led by Prof. Taro Hitosugi and student Yuki Watanabe recently reached a new milestone in this area. These researchers had previously developed a novel memory device inspired by the design of solid lithium-ion batteries. It consisted of a stack of three solid layers made of lithium, lithium phosphate, and gold. This stack is essentially a miniature low-capacity battery that functions as a memory cell; it can be quickly switched between charged and discharged states that represent the two possible values of a bit. However, gold combines with lithium to form a thick alloy layer, which increases the amount of energy required to switch from one state to the other.To read more, click here.