Room-Temperature Ferroelectricity of Paraelectric Oxides Tailored by Nano-Engineering

Abstract

Inducing clear ferroelectricity in the quantum paraelectric SrTiO 3 is important for triggering methods to discover hidden phases in condensed matter physics. Several methods such as isotope substitution and freestanding membranes could introduce ferroelectricity in SrTiO 3 toward nonvolatile memory applications. However, the stable transformation from quantum paraelectric SrTiO 3 to ferroelectricity SrTiO 3 at room temperature still remains challenging. Here, we used multiple nano-engineering in (SrTiO 3 ) 0.65 /(CeO 2 ) 0.35 films to achieve an emergent room-temperature ferroelectricity. It is shown that the CeO 2 nanocolumns impose large out-of-plane strains and induce Sr/O deficiency in the SrTiO 3 matrix to form a clear tetragonal structure, which leads to an apparent room-temperature ferroelectric polarization up to 2.5 μC/cm 2 . In collaboration with density functional theory calculations, it is proposed that the compressive strains combined with elemental deficiency give rise to local redistribution of charge density and orbital order, which induce emergent tetragonality of the strained SrTiO 3 . Our work thus paves a pathway for architecting functional systems in perovskite oxides using a multiple nano-design.

Strategies for the design of ruthenium-based electrocatalysts toward acidic oxygen evolution reaction

“…It can be concluded by the theoretical study that when the O 2p bands were far away from the Fermi level in comparison to the Ru 4d bands, the lattice oxygen was greatly limited and the OER mechanism tended to the adsorbate evolution mechanism (AEM). 78 In contrast, when the O 2p band center got close to the Ru 4d orbital center, the lattice oxygen at the catalyst surface was more likely to take part in the reaction and the OER mechanism was inclined to the lattice oxygen evolution mechanism (LOM) (Fig. 3d).…”

Recent advances of bifunctional electrocatalysts and electrolyzers for overall seawater splitting

“…OER occurs at the anode and is the rate-limiting step in the H 2 production process by water electrolysis. Specically, OER is a four-electron transfer process with a very complex mechanism (e.g., AEM or LOM), 33,34 and a slow kinetic reaction, resulting in a high overpotential.…”

The Promising Seesaw Relationship Between Activity and Stability of Ru‐Based Electrocatalysts for Acid Oxygen Evolution and Proton Exchange Membrane Water Electrolysis

“…Liu et al have demonstrated that higher concentrations of transition metal doping can prompt AEM to switch to LOM by controlling the distribution of Ru 4d and O 2p orbitals, as well as the adsorption energy of intermediates. [54] Overall, the focus of these studies is based on activity regulation, that is, the transition from AEM to LOM. However, more research is needed to investigate the problem of stability degradation caused by a bias towards the LOM mechanism.…”