Boundaries for martensitic transition of (7)Li under pressure.
Nat Commun 2015;
6:8030. [PMID:
26271453 PMCID:
PMC4557344 DOI:
10.1038/ncomms9030]
[Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 07/07/2015] [Indexed: 12/02/2022] Open
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 3 GPa. 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 7 GPa 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 ∼3 GPa, once in fcc phase, lithium does not undergo a martensitic transition.
Lithium metal under extreme pressures shows a sequence of structural phase transitions. Here, the authors use neutron scattering and X-ray diffraction techniques under high pressure to expand the experimental phase diagram of lithium, showing an unexpected deviation from existing boundaries.
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