New probe for the secrets of complex interfaces

In rechargeable batteries, ultra-thin material sheets are crucial. Reactions occur at the interfaces of these sheets. Scientists want to track these reactions. They need a way to probe buried interfaces with elemental specificity. In principle, soft X-ray spectroscopy techniques could be a powerful tool for probing such complex interfaces. However, these techniques haven't been available due to limitations in optics and laser sources. For the first time, an international team devised a soft X-ray second harmonic generation technique and used it to characterize individual layers of graphene inside a graphite sample, promising to open new vistas into the nature of complex interfaces.