Journal
SCIENCE ADVANCES
Volume 4, Issue 11, Pages -Publisher
AMER ASSOC ADVANCEMENT SCIENCE
DOI: 10.1126/sciadv.aat8632
Keywords
-
Categories
Funding
- FRM II
- Feodor Lynen Postdoctoral Research Fellowship of the Alexander von Humboldt Foundation
- Place-to-be RWTH Start-Up fund
- DFG [SFB917]
- NSF-EFRI award [1640860]
- National Science Foundation Research [CHE-1213265]
Ask authors/readers for more resources
The dynamic properties of liquid phase-change materials (PCMs), such as viscosity eta and the atomic self-diffusion coefficient D, play an essential role in the ultrafast phase switching behavior of novel nonvolatile phase-change memory applications. To connect eta to D, the Stokes-Einstein relation (SER) is commonly assumed to be valid at high temperatures near or above the melting temperature T-m and is often used for assessing liquid fragility (or crystal growth velocity) of technologically important PCMs. However, using quasi-elastic neutron scattering, we provide experimental evidence for a breakdown of the SER even at temperatures above T-m in the high-atomic mobility state of a PCM, Ge1Sb2Te4. This implies that although viscosity may have strongly increased during cooling, diffusivity can remain high owing to early decoupling, being a favorable feature for the fast phase switching behavior of the high-fluidity PCM. We discuss the origin of the observation and propose the possible connection to a metal-semiconductor and fragile-strong transition hidden below T-m.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available