Abstract
Physical properties of lithium under extreme pressures continuously reveal unexpected features. These include a sequence of structural transitions to lower symmetry phases, metal-insulator-metal transition, superconductivity with one of the highest elemental transition temperatures, and a maximum followed by a minimum in its melting line. The instability of the bcc structure of lithium is well established by the presence of a temperature-driven martensitic phase transition. The boundaries of this phase, however, have not been previously explored above 3GPa. All higher pressure phase boundaries are either extrapolations or inferred based on indirect evidence. Here we explore the pressure dependence of the martensitic transition of lithium up to 7GPa using a combination of neutron and X-ray scattering. We find a rather unexpected deviation from the extrapolated boundaries of the hR3 phase of lithium. Furthermore, there is evidence that, above ∼3GPa, once in fcc phase, lithium does not undergo a martensitic transition.
| Original language | English |
|---|---|
| Article number | 8030 |
| Journal | Nature Communications |
| Volume | 6 |
| DOIs | |
| State | Published - Aug 14 2015 |
Funding
The authors would like to thank Prof. N. W. Ashcroft for insightful discussions on high pressure properties of lithium. Experimental assistance by Jasmine Bishop is acknowledged. Portions of this work were performed at HPCAT (Sector 16), Advanced Photon Source (APS), Argonne National Laboratory. HPCAT operations are supported by DOE-NNSA under Award No. DE-NA0001974 and DOE-BES under Award No. DE-FG02-99ER45775, with partial instrumentation funding by NSF. The Advanced Photon Source is a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. Research conducted at ORNL’s Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, US Department of Energy. The research in University of Utah was supported by National Science Foundation-Division of Materials Research Award No. 1351986.
