Non-Volatile Memory


The ultrahigh demand for faster computers has driven the search for next-generation nonvolatile memory devices. Currently, the computer is plagued by having to transfer information between the silicon-based random access memory and magnetic-based hard disk drive causing long delays. To overcome this problem, a solution is to develop fast and non-volatile or so-called “universal” memory devices. Here, we control the crystallization kinetics of a non-volatile memory material by prestructural ordering effects. An ultrafast speed of crystallization was achieved. Computer simulations reveal the dynamics and origin of the increase in crystallization speeds. In addition, we modify the crystallization kinetics using the grain size effects and cell size phenomena. The melting dynamics of a material was also controlled using electrostatic interactions and interfacial effects. These pave the way for achieving a broadly applicable memory device, capable of operating at well beyond current data transfer rates.


• Ultrafast non-volatile memory using prestructural ordering processes

• High-endurance non-volatile memory via grain size effects and cell size phenomena

• Low-power non-volatile memory using electrostatic interactions

• Ultralow power non-volatile memory via interfacial effects


1. D. Loke, T. H. Lee, W. J. Wang, L. P. Shi, R. Zhao, Y. C. Yeo, T. C. Chong, S. R. Elliott. Breaking the Speed Limits of Phase-Change Memory. Science 336, 1566-1569 (2012).

2. D. Loke, J. M. Skelton, L. T. Law, W. J. Wang, M. H. Li, W. D. Song, T. H. Lee, S. R. Elliott. Guest-Cage Atomic Interactions in a Clathrate-based Phase-Change Material. Adv. Mater. 26, 1725-1730 (2014).

3. D. Loke, L. P. Shi, W. J. Wang, R. Zhao, L. T. Ng, K. G. Lim, H. X. Yang, T. C. Chong, Y. C. Yeo. Superlatticelike Dielectric as a Thermal Insulator for Phase-Change Random Access Memory. Appl. Phys. Lett. 97, 243508-1-3 (2010).

4. W. J. Wang, D. Loke, L. P. Shi, R. Zhao, H. X. Yang, L. T. Law, L. T. Ng, K. G. Lim, Y. C. Yeo, T. C. Chong, A. L. Lacaita. Enabling Universal Memory by Overcoming the Contradictory Speed and Stability Nature of Phase-Change Materials. Sci. Rep. 2, 360 (2012).

Media coverage


APL Paper on “Superlatticelike Dielectric As A Thermal Insulator for Phase-Change Random Access Memory”

• Keeping the heat on – A*STAR Research

• Better insulation makes phase-change memory work faster, more efficiently – Phys.Org


Science Paper on “Breaking The Speed Limits Of Phase-Change Memory”

• Speedier Data Storage – MIT Technology Review

• ‘Atomic Traffic Jam’ Sheds Light On Phase Changes – RSC Chemistry World

• Write Speeds For Phase-Change Memory Reach Record Limits – Ars Technica

• Boosting Phase-Change Memory Write Speeds – Electronic News

• Speedier Data Storage: Improved Phase-Change Devices Could Replace All Forms of Computer Memory – High Beam Business



• Prof. Dan Hewak, University of Southampton, UK: “The studies by Loke et al., along with related work in other labs, should not only pave the way for phase-change memories with ultrafast switching speeds, low-energy consumption, and reduced memory cell sizes, but also lead to a better understanding of the mechanisms responsible for the phase-change phenomena that could further improve switching speeds.” – Science

• Prof. C. David Wright, University of Exeter, UK: “Such a fast switching means that phase-change memories can compete with conventional silicon-based dynamic random access memories, at least on speed and scaling terms, opening up a potential new application route for phase-change technology.” – RSC Chemistry World

• Dr Robert E. Simpson, (formerly at) Institute of Photonic Sciences, Spain: “Most researchers have tried to improve the switching speed of phase change memory by randomly inserting metals into GST. Learning how to create crystal seeds through simulations and then demonstrating how these seeds speed crystallization in a device is a more scientific approach to developing new memory materials.” – Ars Technica