How does water on the surface of this bizarre material control UV light emission and also its conductivity? Credit: Mohammad A. Islam et al./Nano Letters

Teams of researchers from four American Universities had stumbled on a mysterious property of a material as they were working on it for completely different purposes.

They were studying a layer of lanthanum aluminate on a strontium titanate crystal when they detected a mysterious glow of strong ultraviolet light.

After repeating the experiment several times the researchers discovered the cause: water moisture on the surface. 

During their study of the anomalous UV emission the researchers also detected, even more surprised, a strange conducting state at the interface between the two layers of the material that could also be altered by the water moisture on the outer layer. Additionally the material presented the properties of superconductivity, ferromagnetic ordering and photoconductivity.

According to Fenggong Wang,  theorist that was called in to shed light on the strange phenomena "the dissociation of water fragments on the oxide surface releases electrons that move to the buried interface, cancelling out the ionic charges. This puts the light emission at the same energy, giving the observed sharp photoluminescence".

The researchers suggest that the discovered material could be used as a sensor.

Interesting to see how serendipity is still contributing to the advance of science and technology.

Author - Roberto Saracco

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