Abstract

In this work, the melting line of calcium has been characterized both experimentally, using synchrotron X-ray diffraction in laser-heated diamond-anvil cells, and theoretically, using first-principles calculations. In the investigated pressure and temperature range (pressure between 10 and 40 GPa and temperature between 300 and 3000 K) it was possible to observe the face-centred phase of calcium and to confirm (and characterize for the first time at these conditions) the presence of the body-centred cubic and the simple cubic phase of calcium. The melting points obtained with the two techniques are in excellent agreement. Furthermore, the present results agree with the only existing melting line of calcium obtained in laser-heated diamond anvil cells, using the speckle method as melting detection technique. They also confirm a flat slope of the melting line in the pressure range between 10 and 30 GPa. The flat melting curve is associated with the presence of the solid high-temperature body-centered cubic phase of calcium and to a small volume change between this phase and the liquid at melting. Reasons for the stabilization of the body-centered face at high-temperature conditions will be discussed.

Details

Title
Melting line of calcium characterized by in situ LH-DAC XRD and first-principles calculations
Author
Anzellini Simone 1 ; Alfé Dario 2 ; Pozzo, Monica 3 ; Errandonea, Daniel 4 

 Diamond Light Source Ltd., Didcot, UK (GRID:grid.18785.33) (ISNI:0000 0004 1764 0696) 
 Università di Napoli Federico II, Dipartimento di Fisica Ettore Pancini, Napoli, Italy (GRID:grid.4691.a) (ISNI:0000 0001 0790 385X); University College London, Department of Earth Sciences and London Centre for Nanotechnology, London, UK (GRID:grid.83440.3b) (ISNI:0000000121901201) 
 University College London, Department of Earth Sciences and London Centre for Nanotechnology, London, UK (GRID:grid.83440.3b) (ISNI:0000000121901201) 
 Universidad de Valencia, Departamento de Física Aplicada - Instituto de Ciencia de Materiales, Matter at High Pressure (MALTA) Consolider Team, Valencia, Spain (GRID:grid.5338.d) (ISNI:0000 0001 2173 938X) 
Publication year
2021
Publication date
2021
Publisher
Nature Publishing Group
e-ISSN
20452322
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2554122835
Copyright
© The Author(s) 2021. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.