All That Matters

Photo of the electronic device used to measure the high electron mobility in ZnO. Reprinted by permission from Macmillan Publishers Ltd. Nature Materials (2010). doi:10.1038/nmat2874

Even if you don’t know much about this compound, everybody is familiar with zinc oxide (ZnO). It is a white powder used as the UV-light absorbing component in many sun lotions (and the part of the sun lotion that leaves those white marks on clothes), as an antibacterial agent in some baby powders, in rubbers where it promotes vulcanisation, or as white pigment in colours, and for many other products.

And even now ZnO remains one of the most widely studied oxygen-containing oxide compounds — and this is not going to change anytime soon. In a paper that is now published in my journal Nature Materials, Atsushi Tsukazaki, Masashi Kawasaki and colleagues from Tohoku University in Japan accomplished growing ZnO to such high purity that its electrons can move at extremely high speeds. The material is so clean that it shows quantum effects that are only known from a few very pure compounds. Darrell Schlom from Cornell University in the USA, who works on the growth of oxides, is quite enthusiastic: “Oxides have the unfortunate stigma of being associated with dirt, bricks, and toilet bowls. I love this rags to riches story because it shows that oxides can be clean, so clean that with ZnO they have broken into the most exclusive and elite club that was reserved for just half a dozen of the world’s cleanest materials. This is the greatest achievement of the year for oxides!”

Indeed, the ZnO thin films that Tsukazaki and colleagues grew are so clean that electrons in them move so fast that the researchers were able to observe the so-called Fractional Quantum Hall Effect (FQHE), a first for any oxide compound. The FQHE is a sign that electrons are in quantum states that can be used in quantum computing, and by showing the FQHE, ZnO has established itself as a candidate material for such schemes.

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This morning I read an article by the Scientific American editor David Biello on an important topic: the importance of rare earth elements for our economy, and the power of those few countries that export them on a larger scale. (disclaimer: Scientific American is part of Nature Publishing Group, my employer)

David hits an important point there. But to my mind, the problem is far more critical and fundamental than this single, focussed example suggests, and we need to act on it soon.

Salt production at Salar de Uyuni. This salt flat harbours 50% of the world's lithium reserves. Image by Ricampelo via Wikimedia Commons.

The issue is that rare earth elements such as neodymium are essential to green energy and our economy. Neodymium is part of Nd₂Fe₁₄B, a powerful permanent magnet that is used for electromotors, read heads of hard disk drives, etc. Each wind turbine apparently uses 300 kg of neodymium, each Toyota Prius about 1 kg. At present, China produces 97% of all neodymium.

And this is the problem. China has implemented export controls for its rare earth elements resources. In a recent diplomatic spat with Japan, they temporarily restricted the export of rare earth elements to Japan. But the Chinese should not take all the blame for a little realpolitik. Heard of the 1973 oil crisis?

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Bleak prospects

Today I take a break from my usual blogging on scientific research to highlight an issue of more immediate concern: the threat to the scientific infrastructure in the UK and elsewhere.

The 2007/2009 recession hit us all. Those that own houses had their value reduced. Those that are just about to finish university have to worry about possibly being part of a lost generation of highly educated graduates not being able to find employment. Those that always had to struggle making ends meet are affected by savings to government services and by problems arranging bank credits. And some of our governments now find themselves in deep budget deficits.

This is the broader reason why some governments, like the US, like Japan, like the UK, are now considering cuts to their budget. In the UK, the situation is particularly severe, and this is why here I like to focus on this example even though the same principles would apply elsewhere as well.

The UK government aims to implement a cut of 25% in overall government spending across all areas, even though out of a total annual government budget of about 670 billion pounds, science has only a share of 6 billion. The implications could be severe. A scenario where the science budget is cut by 20% has been described by a Royal Society analysis as “game over”.

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