Negative thermal expansion of ScF3: Insights from density-functional molecular dynamics in the isothermal-isobaric ensemble

作者：Lazar Petr^*; Bucko Tomas; Hafner Juergen

来源：Physical Review B, 2015, 92(22): 224302.

DOI：10.1103/PhysRevB.92.224302

Scandium trifluoride (ScF3) is a rare example of a material with a simple structure exhibiting a large negative thermal expansion over a wide range of temperatures. In the present work, the thermal behavior of this material has been studied by means of density-functional molecular dynamics in the isothermal-isobaric ensemble. Our simulations reproduce the experimentally observed trends: thermal expansion is negative at low temperatures, approaches zero at approximate to 1000 K, and is positive at higher temperatures. The simulations permit us to develop an atomistic scenario of the observed phenomena, which arises from the correlated dynamics of ScF6 octahedra. The relation between the cubic-to-rhombohedral transformation under a very modest compression and the thermal behavior of ScF3 is demonstrated.

• 出版日期2015-12-1