All That Matters

The past year has been a great year for science with major advances in several areas. Too many exciting results to mention here. Instead, to reflect about the past year I have chosen a representative paper for each month of the year that I hope can serve as an example of the great science going on in a number of research fields. Of course, this is a highly subjective and personal collection, and indeed there might be others worth mentioning. But the aim was also to provide a balanced overview of the year that covers a variety of topics.

Of course, if you have an exciting paper to add, please feel free to use the comments section below to let us know!

Anyway, enough said, here are some of my highlights from the past year:

Simulations of electronic excitations in an iron-based superconductor. Image by Oak Ridge National Laboratory via flickr.

JANUARY – iron-based superconductors

Since they were discovered in 2008, iron-based superconductors, the pnictides, have been one of the hottest topics in condensed matter physics. Part of their appeal stems from the fact that they are based on iron, which is a magnetic element. Normally, magnets and superconductivity exclude each other.

The iron-based compounds have a similar crystal structure as the so-called cuprates, which are the materials with the highest superconducting temperatures known. The mechanism for these high-temperature superconductors is unknown, and studying the iron-based superconductors may also be relevant to the understanding of the cuprates.

This paper published in Science shows for the first time that the electrons in the iron-based superconductors show a periodic arrangement that is different to the periodicity of the atoms in the crystal. Similar observations have been made in the cuprates, and their understanding is considered important to the mechanism of high-temperature superconductivity.

Chuang, T., Allan, M., Lee, J., Xie, Y., Ni, N., Bud’ko, S., Boebinger, G., Canfield, P., & Davis, J. (2010). Nematic Electronic Structure in the “Parent” State of the Iron-Based Superconductor Ca(Fe1-xCox)2As2 Science, 327 (5962), 181-184 DOI: 10.1126/science.1181083

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Photo by anttler via flickr

Designing organic molecules that perform repeated mechanical motions is not easy. The molecule needs to be robust on the one hand, and on the other hand have different stable states between which it can alternate. Achieving such complex functionality requires careful design considerations. Nature has solved this problem, and molecular motors perform important functions in living organisms, for example in enzymes.

The design and synthesis of artificial mechanical molecules performing specific functions remains a challenge. For example, molecular rotors have been fabricated before, but only showed limited functionality: their direction of rotation could not be reversed. […]

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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