講演情報
[25a-32A-4]Anisotropic thermal expansion phenomena in Ca2RuO4 type systems
〇Hena Das1,2, Masaki Azuma2,1 (1.Kanagawa Institute of Industrial Science and Technology (KISTEC), 705-1 Shimoimaizumi, Ebina 243-0435, Japan, 2.Laboratory for Materials and Structures, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, Kanagawa 226-8503, Japan)
キーワード：
Negative thermal expansion、Computational materials science、Complex oxides
Thermal strains in functional materials can seriously impede their device applications. It is thus, a technological imperative to minimize the thermal expansion of materials. Negative thermal expansion (NTE), a rare and interesting phenomenon observed in certain materials which contract upon heating, can be effectively harnessed to this end. Layered Ca2RuO4 is one such material endowed with this characteristic exhibiting a giant NTE within a 200 K temperature window with a value of ~ -115 x 10-6 /K of the linear coefficient of thermal expansion1,2. While the phenomenon was attributed to the observed anisotropic thermal expansion (ATE), the exact microscopic mechanisms remain unclear. In my presentation, I will elaborate upon the couplings between various order parameters and their impact on the thermal expansion properties of this system. I will discuss the role anharmonic effects which are of higher order than their counterparts in the quasi-harmonic approximation. I will also discuss our findings of high-throughput search for new NTE materials within layered K2NiF4 lattice framework.
[1] K. Takenaka et al., Nat. Commun. 8, 14102 (2017).
[2] L. Hu et al., Chem. Mater. 33 (19), 7665-7674 (2021).
[1] K. Takenaka et al., Nat. Commun. 8, 14102 (2017).
[2] L. Hu et al., Chem. Mater. 33 (19), 7665-7674 (2021).