Defect‐Induced, Ferroelectric‐Like Switching and Adjustable Dielectric Tunability in Antiferroelectrics

Abstract

Antiferroelectrics, which undergo a field‐induced phase transition to ferroelectric order that manifests as double‐hysteresis polarization switching, exhibit great potential for dielectric, electromechanical, and electrothermal applications. Compared to their ferroelectric cousins, however, considerably fewer efforts have been made to understand and control antiferroelectrics. Here, it is demonstrated that the polarization switching behavior of an antiferroelectric can be strongly influenced and effectively regulated by point defects. In films of the canonical antiferroelectric PbZrO3, decreasing oxygen pressure during deposition (and thus increasing adatom kinetic energy) causes unexpected “ferroelectric‐like” polarization switching although the films remain in the expected antiferroelectric orthorhombic phase. This “ferroelectric‐like” switching is correlated with the creation of bombardment‐induced point‐defect complexes which pin the antiferroelectric–ferroelectric phase boundaries, and thus effectively delay the phase transition under changing field. The effective pinning energy is extracted via temperature‐dependent switching‐kinetics studies. In turn, by controlling the concentration of defect complexes, the dielectric tunability of the PbZrO3 can be adjusted, including being able to convert between “positive” and “negative” tunability near zero field. This work reveals the important role and strong capability of defects to engineer antiferroelectrics for new performance and functionalities.

Research status and prospect of lead zirconate-based antiferroelectric films

“…8 该发现颠覆了长期以来对PZO相变过程的传统认知 [47] ；此外，Si上面生长的PZO 多晶薄膜研究中也观察到具有不相称的调制特性的FiE结构 [7] ，如图3(b)所示， 这是由于长程FE相和短程AFE相之间的竞争失败，在这种情况下，未补偿的不相 称调制转化为零电场下的净剩余极化；Lane W. Martin等通过改变脉冲激光沉积 过程中的氧压(从而改变原子动能和随后的轰击效应)，发现反铁电PZO薄膜的 极化行为可以受到点缺陷的强烈影响，沉积过程中氧压的降低导致了意想不到的 "类铁电"特性，并且通过电场调节可以观察到从AFE到"类铁电"的有趣演变 [48] ， 如图3(c)所示。到目前为止关于AFE薄膜中弱FE的结构和性能认识都没有达到 共识，由于薄膜易受到界面、应变、缺陷等因素影响，AFE薄膜中观察到的非中 心对称结构和弱FE行为是否为本征特性，尚待进一步考证。 2.2 电学特性 图4 (a) PZO块体的介电温谱图 [3] ；(b) PZO基反铁电薄膜的C-V特性曲线 [52] ；(c) PZO薄膜的P-E和I-E回线 [50] ； (d) PZO薄膜在直流电场E DC 和交流电场E AC 作用下的 电致应变和压电系数 [7] Fig. 4.…”

“…a) 改变电子束辐照时间同一区域PZO薄膜的电场驱动相变行为 [47] ；(b) 从 (001)和(042)取向PZO薄膜中铅离子位移提取的极化构型 [7] ；(c) 不同生长氧压 (120mTorr，80mTorr和45mTorr) PZO薄膜的极化行为 [48] Fig. 3.…”

“…3. (a) Phase-boundary-driven phase transition in PZO films under the irradiation of an electron beam [47] ; (b) Polarization configurations extracted from Pb ions displacements in (001) and (042) oriented PZO films [7] ; (c) Polarization-electric field loops of PZO grown at various oxygen pressures (120 mTorr, 80 mTorr and 45 mTorr) [48] .…”

Nonlinear Optical Switching in a Tin-Based Multilayered Halide Perovskite Activated by Stereoactive Lone Pairs and Confined Rotators

“…Nonlinear optical (NLO) materials, which generate a cascaded second harmonic generation (SHG) response when stimulated by an applied optical field, have drawn widespread attention for the development of all-solid-state laser devices in various advanced laser technologies. − As one of the new research branches, NLO switches with controllable and switchable SHG responses have attracted increasing interest. − It is known that the SHG response in the NLO switches undergoes a reversible transformation between SHG-on and SHG-off states under external control signals, which shows great potential for prominent modulations in burgeoning optoelectronic technologies, e.g., biological sensors, data memories, and optical communication networks. − Notably, this transformation can be dynamic, allowing the switch to be actively controlled. , As a result, impressive efforts have been concentrated on the exploration of NLO switches driven by solid-state structural phase transitions, which are considered to be one of the most efficient, stable, and promising strategies. − Over the past few decades, considerable progress has been achieved in developing solid-state NLO switches in several material systems, such as inorganic salts, organic molecules, and host–guest inclusion compounds …”

Hydrogen Bond Reorganization‐Enabled Dielectric Pulsing Effects in Polar Polymers

“…The results indicate that, under thermal stimulation, the dielectric constant of thermo-responsive dielectric materials that may meet the above application requirements can undergo bistable, [13][14][15][16][17][18][19][20][21][22] linear, [23] pulsed, [24][25][26][27][28] or other response forms. [29,30] This phenomenon is called thermo-responsive dielectric behavior. The dielectric response behavior can be based on mechanisms such as dipole polarization, interfacial polarization, and electrode polarization, and can be enhanced by selecting, tuning, or designing the material polarity, molecular motility, interfacial structure, and percolation network, suggesting promising fabrication strategies for these materials.…”