Revealing the Anisotropy in Protonation-Induced Electronic Phase Transitions of Rare-Earth Nickelates within a Marine Environment

Abstract

Although the discovery of the electrochemical protonation-induced electronic phase transition of rare-earth nickelates (ReNiO3) enables potential application in sensing the ocean electric field that simulates the working principle of the ampullary organ of marine animals, whether such a functionality is anisotropic is previously overlooked. Herein, we demonstrate the anisotropy in the protonation-induced electronic phase transition in ReNiO3 (Re = Sm, Nd, and Eu) thin films as electrochemically triggered in an ocean environment. A larger elevation in the material resistivity triggered by an electric field within an ocean environment is observed for ReNiO3/LaAlO3(110), compared to ReNiO3/LaAlO3(001) and ReNiO3/LaAlO3(111). This is attributed to the orientation-related in-plane oxygen atomic density that results in more effective in-plane proton diffusion along the adjacent oxygen position, as further confirmed by the electrochemical cyclic voltammetry characterization. In addition, the larger activation energy associated to the anisotropic in-plane electronic structures of ReNiO3/LaAlO3(110) is also expected to promote the formation of electron-localized orbital configurations upon hydrogenation. As demonstrated, anisotropy sheds light on another possibility that can be further introduced to regulate the protonation-induced electronic phase transition properties of ReNiO3 for its potential applications such as ocean electric field sensing or biosensing.

Research on the electronic phase transitions in strongly correlated oxides and multi-field regulation

“…此外, 研究者们将强关联电 子相变氧化物材料作为场效应晶体管 (FET) 的沟道层, 利用栅极偏压注入电子、 质子及氧空位等, 可利用电场控制的离子调控方法在关联氧化物中实现比传统 静电门控更大的载流子密度(~10 15 cm -2 ), 触发可逆非易失的电阻开关效应(图 6a), 构筑出新型关联电子原型器件 [51] , 探索强关联电子相变氧化物材料体系中 源于非平衡态的新型电子相和关联输运行为(图 6b) [71] . S. Ramanathan 等人基 于模拟鲨鱼洛伦兹壶腹的核心思想, 利用弱电场调控海洋环境中质子空间分布 诱导 SmNiO 3 电阻变化的原理, 构筑出海洋弱电场传感原型器件 [14] ; 李海帆等人 进一步证实由于 SmNiO 3 不同晶体学取向间氧原子致密度的差异, 弱电场触发海 洋化境中 SmNiO 3 材料电阻的变化值具有明显的各向异性, 如下图 6c-6d 所示 [72] .…”

“…图 6 特征电场调控氢化强关联氧化物的电子相变特性 (a) 特征电场触发 VO 2 可逆的氢致电子相变 [5] ; (b) 特征电场诱导氢化 SmNiO 3 中类二极管的奇异输运 行为 [71] ; (c) SmNiO 3 基海洋电场传感器原理图 [72] ; (d) SmNiO 3 海洋电场传感的晶 体学各向异性 [72] Fig. 6.…”

Hydrogen‐Associated Multiple Electronic Phase Transitions for d‐Orbital Transitional Metal Oxides: Progress, Application, and Beyond

“…[92][93][94][95] In contrast to other MIT family of materials, the overwhelming advantage of the ReNiO 3 is associated with their adjustable T MIT within a broad temperature range from 130 (PrNiO 3 ) to 600 K (LuNiO 3 ) via simply altering the rare-earth compositions. [95][96][97][98] The physical origin associated with the MIT behavior of ReNiO 3 as triggered by a critical temperature is attributed to the charge disproportionation of Ni 3+ (e.g., Ni 3+ ↔Ni 3±Δ ) that splits a charge-transfer band gap between Ni-3d and O-2p orbitals. Such MIT properties in ReNiO 3 are highly correlated with the distortion of their NiO 6 octahedron.…”

“…Recently, correlated TMOs (e.g., SmNiO 3 ) were revealed to be utilized as the detector for sensing the bioelectric field within a marine environment via the oceanic-electric-field-induced electronic phase modulations. [13,98] Simulating the working principle associated with the ampullar organ of marine animals, Z. Zhang et al discovered electrochemical protonation-induced electronic phase transition for SmNiO 3 within the marine environment (e.g., 0.6 m NaCl solution) (Figure 13a). Hydrogens as electrolyzed from the aqueous solution via imparting an electric potential are intercalated into the lattice of SmNiO 3 that results in the electron localizations to enlarge the material resistance via on-site Coulomb repulsion in e g orbital.…”

“…In addition, H.F. Li et al further revealed the anisotropy in such water-mediated electronic phase transitions of ReNiO 3 films (Re = Sm, Nd, Eu) as deposited on the differently oriented LaAlO 3 substrates within the marine environment, as schematically illustrated in Figure 13b. [98] The anisotropic protonation can be attributed to the orientation-dependent in-plane oxygen atomic density, which facilitates more efficient in-plane proton diffusion along adjacent oxygen positions. This is confirmed by the resistance switching ratio observed when applying a polarized bias voltage (±0.5 V), as shown in Figure 13c.…”