Exploring the limits of phase change memories

Phase change materials are among the most promising compounds in information technology. They can be very rapidly switched between the amorphous and the crystalline state, indicative for peculiar crystallization behaviour. Phase change materials are already employed in rewriteable optical data storage, where the pronounced difference of optical properties between the amorphous and crystalline state is used. This unconventional class of materials is also the basis of a storage concept to replace flash memory. This talk will discuss the unique material properties which characterize phase change materials. In particular, it will be shown that the crystalline state of phase change materials is characterized by the occurrence of resonant bonding, a particular flavour of covalent bonding. This insight is employed to predict systematic property trends and to develop non-volatile memories with DRAM-like switching speeds potentially paving the road towards a universal memory. Phase change materials do not only provide exciting opportunities for applications including ‘greener’ storage devices, but also form a unique quantum state of matter as will be demonstrated by transport measurements. In this talk, potential limits of phase change memories in terms of switching speed, scalability and power consumption will be discussed.