近日，奥地利科学技术研究所Scott R. Waitukaitis团队报道了不定形碳在氧化物接触带电过程中破坏对称性。2026年3月18日，《自然》杂志发表了这一成果。

绝缘氧化物是宇宙中含量最丰富的固体材料之一。在它们影响自然现象的众多方式中，最重要的或许是在接触过程中传递电荷的能力——即便是在同种氧化物样品之间也会发生这种现象，然而导致这一现象的对称破缺因子至今尚未明确。

研究组表明，从环境中吸附的外源碳质分子是同种材料氧化物接触起电中的对称破缺因素。研究组利用声悬浮技术测量了由相同非晶态二氧化硅构成的球体与平板之间的电荷交换。尽管共制备样品的带电极性呈现随机性，但通过烘烤或等离子体处理可实现对其调控。

在观测随后的电荷交换弛豫过程时，研究组发现其动力学行为跨越数小时时间尺度，并通过飞行时间质谱、低能离子散射和红外光谱将其与外源碳的存在直接关联。进一步研究证实，外源碳甚至能决定不同氧化物之间的电荷交换。该研究结果不仅确定了导致绝缘氧化物在沙漠沙尘到火山烟羽等环境中发生电荷交换的对称破缺因子，同时也揭示了接触起电领域中一个长期被忽视的关键因素。

附：英文原文

Title: Adventitious carbon breaks symmetry in oxide contact electrification

Author: Grosjean, Galien, Ostermann, Markus, Sauer, Markus, Hahn, Michael, Pichler, Christian M., Fahrnberger, Florian, Pertl, Felix, Balazs, Daniel M., Link, Mason M., Kim, Seong H., Schrader, Devin L., Blanco, Adriana, Gracia, Francisco, Mujica, Nicols, Waitukaitis, Scott R.

Issue&Volume: 2026-03-18

Abstract: Insulating oxides are among the most abundant solid materials in the universe1,2,3. Of the many ways in which they influence natural phenomena, perhaps the most consequential is their capacity to transfer electrical charge during contact4,5,6,7,8,9,10—which occurs even between samples of the same oxide—yet the symmetry-breaking parameter that causes this remains unidentified11,12. Here we show that adventitious carbonaceous molecules adsorbed from the environment are the symmetry-breaking factor in same-material oxide contact electrification (CE). We use acoustic levitation to measure charge exchange between a sphere and a plate composed of identical amorphous silicon dioxide (SiO2). Although charging polarity is random for co-prepared samples, we control it with baking or plasma treatment. Observing the charge-exchange relaxation afterwards, we see dynamics over a timescale of hours and connect this directly to the presence of adventitious carbon with time-of-flight mass spectrometry, low-energy ion scattering and infrared spectroscopy. Going further, we confirm that adventitious carbon can even determine charge exchange among different oxides. Our results identify the symmetry-breaking parameter that causes insulating oxides to exchange charge in settings ranging from desert sands4 to volcanic plumes5,6, while simultaneously highlighting an overlooked factor in CE more broadly.

DOI: 10.1038/s41586-025-10088-w

Source: https://www.nature.com/articles/s41586-025-10088-w