“Reports of my death have been greatly exaggerated,” Mark Twain allegedly said after his obituary was published prematurely. High-temperature superconductivity physicists now know how he felt.

If current trends continue, research into high-temperature superconductivity (high Tc) will come to a standstill some time between 2010 and 2015, according to a report by Andreas Barth and Werner Marx, respectively at FIZ Karlsruhe and the Max Planck Institute for Solid State Research in Stuttgart, Germany. That news hasn't gone down well.

Barth and Marx scoured databases owned by the Chemical Abstracts Services (CAS) and the physics and engineering abstracts service Inspec to find how interest in the field was holding up. They searched for all papers published and patents granted until the end of 2005 that involve alkaline earth cuprates containing rare earth elements. These materials show extremely low resistance to electricity at temperatures up to around −200 °C. This is much warmer than temperatures normally associated with superconductors. But nobody has been able to work out how such high-temperature superconductors work.

Barth and Marx plotted the falling number of publications over time, then extrapolated the results to predict that the number of publications on these compounds will drop to zero between 2010 and 2015 “if no ground-breaking discoveries happen to occur”.

Superconductivity scientists admit the field has slowed since the flurry of research that followed Georg Bednorz and Alex Müller's 1987 Nobel prize for their discovery of ceramic high-temperature superconductors. “There was a gold rush,” says Jan Zaanen of Leiden University, the Netherlands. “It's a very deep problem — all the easy things have been done.”

“All fields of condensed-matter physics undergo periods of ebb and flow,” says Paul Grant, who has worked at IBM on high-temperature superconductors. “The general field of superconductivity is wide open.”

After high-temperature superconductivity was discovered there was a huge spike in publications. Dreams of creating levitating trains, making a fortune and getting a Nobel prize for finding out how these systems work kept the field alive for a while. But as problems remained unsolved, people started to leave. “High Tc made me feel old,” says Zaanen. Only the diehards remained, he says, some of whom acquired reputations for having large egos and even making superconductivity something of a religion. Zaanen claims those egos have been toned down but says the field is still too intimidating to attract young blood.

Barth and Marx did not include such influences as these in their study. Marx says his aim was to “demonstrate the potential of databases and search systems for generating meta-information that could be interesting in a specific field”. As a piece of scientometrics the work is robust, according to Paul Peters, who works at the CAS: “Given the fact that multiple sources and different approaches all indicate the same demise, I would think this is quite accurate.”

A magnet levitates above a ceramic superconductor cooled by liquid nitrogen. Credit: D. PARKER/IMI/UNIV. BIRMINGHAM HIGH TC CONSORTIUM/SPL

But he warns: “Science may prove them wrong.” There are signs that high-temperature superconductivity could be having a resurgence. The US Department of Energy's basic energy sciences office recently ran a workshop on superconductivity. Pat Dehmer, the office's associate director, says: “Funding will be very seriously considered for this field,” although she remains coy about revealing details before the federal budget announcement in February. A demonstration project using high-temperature superconductor wires in the US national energy grid is also starting this year.

Marx agrees that the field could revive given a breakthrough such as the discovery of superconductors that work at even higher temperatures or are in a new class of materials, or the development of a theoretical explanation of the phenomenon. He also admits that his study has limitations. “Extrapolations are always problematic,” he says. “The word 'zero' is perhaps not an optimal expression here. It may be taken seriously but certainly not literally.”

That doesn't stop some from taking the conclusion personally. The extrapolation is “utter nonsense” according to Zaanen. “It's a vivid illustration of the blindness of bean counting.”