Control of (oxygen) stoichiometry of correlated materials by ionic liquid gating

通过离子液体门控控制相关材料的（氧）化学计量

• 批准号: 388006450
• 负责人: Dr. Simone Altendorf
• 金额: --
• 依托单位: Abteilung Physik korrelierter Materie (PCM)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/388006450?language=en
• 关键词: Control; oxygen; stoichiometry; correlated; materials

Ionic liquid (IL) gating is a powerful tool to significantly alter the physical properties of thin films using relatively low voltages and temperatures. Initially insulating oxides like e.g. VO2 and WO3 can be fully and reversibly volume metallized by applying a gate voltage of only 2-3V across the IL. Although it has been proven for various materials that electrochemical processes play an important role in the IL gate-induced effects, the exact mechanisms are still under discussion and numerous contradictory results published. One possible origin underlying these controversial results might be a lack of purity of the experimental conditions which commonly involve ex-situ processes for the IL device preparation. In this project, we aim to perform a true all in-situ/ultra-high vacuum IL gating study to avoid any influence of contamination or degradation effects of sample surface or IL. Using this all in-situ experiment, we intend to investigate in a first step in detail the mechanisms of the IL gate-induced changes, for instance by carefully determining the number of oxygen vacancies created or refilled in the gating process. Then, we will actually utilize IL gating to tune the oxygen content of correlated materials for systematic stoichiometry dependent studies, and possibly even synthesize chemical phases which usually require extreme conditions to be prepared or are not at all stable.

离子液体（IL）门控是一个强大的工具，显着改变薄膜的物理性质，使用相对较低的电压和温度。通过在IL两端施加仅2-3V的栅极电压，可以完全且可逆地体积金属化初始绝缘氧化物（例如VO 2和WO 3）。虽然已经证明了各种材料的电化学过程中起着重要作用的IL门诱导的效果，确切的机制仍在讨论中，许多矛盾的结果公布。这些有争议的结果背后的一个可能的起源可能是缺乏纯度的实验条件，通常涉及非原位过程的IL设备的制备。在这个项目中，我们的目标是进行一个真正的所有原位/超高真空IL门控研究，以避免任何污染或样品表面或IL的降解效应的影响。使用这种全原位实验，我们打算在第一步中详细研究IL栅极引起的变化的机制，例如通过仔细确定在门控过程中产生或重新填充的氧空位的数量。然后，我们将实际利用IL门控来调整相关材料的氧含量，以进行系统的化学计量依赖性研究，甚至可能合成通常需要极端条件才能制备或根本不稳定的化学相。