Researchers examine competing states in high-temperature superconductors

December 6, 2018, Karlsruhe Institute of Technology
To apply controlled pressure to their microscopic superconducting sample (graphics), researchers use sensitive brackets with actuators based on the piezoelectric effect. Credit: KIT

High-temperature superconductors can transport electrical energy without resistance. Researchers at Karlsruhe Institute of Technology (KIT) have carried out high-resolution inelastic X-ray scattering and have found that high uniaxial pressure induces a long-range charge order competing with superconductivity. Their study opens up new insights into the behavior of correlated electrons. The study is published in Science.

Superconductors transport current without losses, but only below a certain . Conventional superconductors need to be cooled down almost to absolute zero, and even the so-called require temperatures of around -200 degrees Celsius to transport current without resistance. Despite this, superconductors are already in widespread use. To develop superconductors that work at even higher temperatures—possibly up to —and therefore significantly contribute to an efficient energy supply, and processes involved in the formation of the superconducting condensate need to be understood at a fundamental level.

Researchers led by Professor Matthieu Le Tacon, director of the Institute of Solid-State Physics (IFP) at KIT, have now made a significant step forward. They have shown that high uniaxial pressure can be used to tune the competing states in a high-temperature superconductor. Using high-resolution inelastic X-ray scattering, the scientists examined a high-temperature cuprate superconductor, YBa2Cu3O6.67. In this complex compound, copper and oxygen atoms form two-dimensional structures. Changing the charge carrier concentration in these planes yields a variety of electronic phases including superconductivity and charge orders.

In the charge ordered state, the electrons 'crystallize' into stripe-shaped nanostructures. This electronic state is usually observed in these materials when superconductivity is suppressed using very large magnetic fields, making it hard to investigate using conventional spectroscopic tools.

Inducing this state in YBa2Cu3O6.67 using uniaxial pressure instead of magnetic fields allowed the researchers to study its relationship to superconductivity using X-ray scattering. They identified strong anomalies of the lattice excitation connected to the formation of the charge order. "Our results provide new insights into the behavior of electrons in correlated electron materials and into the mechanisms yielding to high-temperature superconductivity," says Professor Matthieu Le Tacon from KIT. "They also show that uniaxial pressure has the potential to control the order of the electrons in such materials."

Explore further: Surprising similarity between stripy black holes and high-temperature superconductors

More information: H.-H. Kim et al, Uniaxial pressure control of competing orders in a high-temperature superconductor, Science (2018). DOI: 10.1126/science.aat4708

Related Stories

Superconducting secrets solved after 30 years

June 17, 2014

( —A breakthrough has been made in identifying the origin of superconductivity in high-temperature superconductors, which has puzzled researchers for the past three decades.

Recommended for you

Researchers design technology that sees nerve cells fire

December 13, 2018

Researchers at Stanford University, Palo Alto, California, have created a noninvasive technology that detects when nerve cells fire based on changes in shape. The method could be used to observe nerve activity in light-accessible ...

Copper compound as promising quantum computing unit

December 12, 2018

Quantum computers could vastly increase the capabilities of IT systems, bringing major changes worldwide. However, there is still a long way to go before such a device can actually be constructed, because it has not yet ...

New method gives microscope a boost in resolution

December 12, 2018

Scientists at the University of Würzburg have been able to boost current super-resolution microscopy by a novel tweak. They coated the glass cover slip as part of the sample carrier with tailor-made biocompatible nanosheets ...

How bacterial communities transport nutrients

December 12, 2018

Under threat of being scrubbed away with disinfectant, individual bacteria can improve their odds of survival by joining together to form colonies, called biofilms. What Arnold Mathijssen, postdoctoral fellow in bioengineering ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.