Programme

O.4 -- Oral

Date: Friday, 24 November 2017

Time: 14:35 - 14:55

Quartic Anharmonicity and Negative Thermal Expansion of ScF₃

Tipaporn Patniboon (1), Sirichok Jungthawan (1,2,3,*), Sukit Limpijumnong (1,2,3)

(1) School of Physics, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand; (2) NANOTEC-SUT Center of Excellence on Advanced Functional Nanomaterials, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand; (3) Thailand Center of Excellence in Physics (ThEP), Commission on Higher Education, Bangkok 10400, Thailand

ScF$_{3}$ exhibits negative thermal expansion (NTE) over a range of temperatures. The underlying mechanism is attributed to a rigid unit mode (RUM) which can be explained by Li et al. [Phys. Rev. Lett. 107, 195504 (2011)] in terms of the vibration mode with the transverse motion of anion atoms to their bond direction. It has been found that this mode behaves as quantum quartic oscillator. In this work, frozen phonon calculations with first-principles calculations based on the density functional theory (DFT) have been performed to compare the degree of NTE between ScF$_{3}$ and ReO$_{3}$. It has been found that the quadratic and quartic behaviors strongly depend on the bonding character between cation and anion atoms.

Presenter: Sirichok Jungthawan