Superconductors earn their stripes

Now a team led by scientists from the Max Planck Institute for Structure and Dynamics (MPSD) has provided the first evidence of a hidden superconducting state above the superconducting transition temperature. Such a state has been elusive to detect since it is invisible to most experimental probes. The work is published in Science.

Rajasekaran and coworkers used new terahertz techniques to detect this striped superconductivity above the superconducting transition temperature in cuprates. It occurs because the fluid carrying lossless currents is not homogenously distributed, but arranges itself in stripes: one-dimensional rivers that rotate by ninety degrees along one axis of the crystal.

Superconductivity, a phenomenon involving the lossless transport of electricity, was first observed in metals cooled almost to absolute zero (~ 270 degrees Celsius). Over the last few decades other ceramic materials such as doped copper oxides (cuprates) have been discovered, where superconductivity occurs at much higher temperatures (Tc ~ -150 degrees Celsius). The mechanism behind this high temperature superconductivity remains a mystery.

Cooled cuprates not only develop superconductivity but also host other states that interact with the superconducting fluid. Especially interesting is a state that appears to be intertwined with the superconductor, where the fluid is arranged in a spatially modulated, rather than a homogeneous fashion. Although such striped superconductors do not carry supercurrents efficiently, their manipulation may be used to enhance the temperature for superconductivity.

Cuprate superconductors are in fact layered materials with alternating superconducting and insulating planes. The superfluid phase is formed in each layer, and three-dimensional superconductivity is made possible by quantum mechanical tunneling in the direction perpendicular to the planes.

In a striped superconductor, tunneling currents are identically zero. That is, these currents flow at each point in space, but the sum over space vanishes identically. Hence, it is difficult ot detect the presence of the striped superconductor.

Rajasekaran, Cavalleri and coworkers tackled this problem by driving strong tunneling currents, far in excess of the levels usually used to diagnose the presence of a superfluid. In their geometry, the tunneling was observed to be no longer zero even in case of striped superconductivity.

Together with theory colleagues from Ludwig Mathey's group at the University of Hamburg, the MPSD scientists have also provided a quantitative description of the results, which now rest on a solid theoretical foundation.

This study, largely related to previous works in the Cavalleri group aimed at manipulating hidden superconductivity in complex materials, opens up new possibilities to study other types of hidden orders in many other condensed matter systems.

Contact:

Jenny Witt, MPSD PR and communications officer
Tel. +49 175 702 3930
Email: jenny.witt@mpsd.mpg.de

http://science.sciencemag.org/content/359/6375/575
https://doi.org/10.1126/science.aan3438
http://www.mpsd.mpg.de

Media Contact

Jenny Witt Max-Planck-Institut für Struktur und Dynamik der Materie

All latest news from the category: Physics and Astronomy

This area deals with the fundamental laws and building blocks of nature and how they interact, the properties and the behavior of matter, and research into space and time and their structures.

innovations-report provides in-depth reports and articles on subjects such as astrophysics, laser technologies, nuclear, quantum, particle and solid-state physics, nanotechnologies, planetary research and findings (Mars, Venus) and developments related to the Hubble Telescope.

Back to home

Comments (0)

Write a comment

Newest articles

The Sound of the Perfect Coating

Fraunhofer IWS Transfers Laser-based Sound Analysis of Surfaces into Industrial Practice with “LAwave”. Sound waves can reveal surface properties. Parameters such as surface or coating quality of components can be…

Customized silicon chips

…from Saxony for material characterization of printed electronics. How efficient are new materials? Does changing the properties lead to better conductivity? The Fraunhofer Institute for Photonic Microsystems IPMS develops and…

Acetylation: a Time-Keeper of glucocorticoid Sensitivity

Understanding the regulatory mechanism paves the way to enhance the effectiveness of anti-inflammatory therapies and to develop strategies to counteract the negative effects of stress- and age-related cortisol excess. The…

Partners & Sponsors