ESPCI web site
May 7 at 2:00 pm (Paris time)
Room Charpak
Control of thermal conductivity in ferroelectric and ferroelastic materials
Since the early days of computing, hardware has evolved from mechanical to digital systems, where logic operations are performed by controlling electrons in semiconductors. However, the development of semiconductor-based chips is encountering important bottlenecks. To be disruptive, future progress is expected to be driven by different information carriers. Here, we argue that oxides are the ideal solid-state materials for a new type of computing based on thermal currents rather than electric currents [1]. We show that ferroelastic domain walls behave as boundaries that act like efficient controllers to govern thermal conductivity. At low temperature (3 K), in ferroelastic LaAlO3, we demonstrate a fivefold reduction in thermal conductivity induced by domain walls orthogonal to the heat flow and a twofold reduction when they are parallel to the heat flow [2]. At room temperature, we also report in improper ferroelectric ErMnO3 polycrystals a decrease in thermal conductivity with increasing grain size. This unusual relationship between heat transport and microstructure is attributed to phonon scattering at ferroelectric domain walls [3]. Finally, we predict by ab initio electronic structure calculations that ferroelectric domains in BaTiO3 exhibit anisotropic thermal conductivities. We confirm this prediction by combining frequency-domain thermoreflectance and scanning thermal microscopy measurements on a single crystal of barium titanate. We then use this gained knowledge to propose a lead-free thermal conductivity switch operating reversibly with an electric field [4].
[1] Nataf et al. Using oxides to compute with heat. Nat. Rev. Mater. 9, 530–531 (2024)
[2] Limelette et al. Influence of ferroelastic domain walls on thermal conductivity. Phys. Rev. B 108, 144104 (2023)
[3] Belrhiti‐Nejjar et al. Domain‐Wall Driven Suppression of Thermal Conductivity in a Ferroelectric Polycrystal. Adv. Sci. 06931, 1–7 (2025)
[4] Féger et al. Lead-free room-temperature ferroelectric thermal conductivity switch using anisotropies in thermal conductivities. Phys. Rev. Mater. 8, 094403 (2024)
