High-temperature superconductors are ceramic materials and produce the most powerful correlations between electrons in nature. These correlations describe the interdependencies of electrons in the material and are the basis for the possible application of these materials in the next generation of computing and data transmission. Differently from conventional superconductors, in a strongly-correlated system, the interaction between electrons is considered to play an important role. For most weakly-correlated materials, a superconducting state is only reached in a cryogenic atmosphere, at temperatures around -269°Celsius. High-temperature conductors, however, reach this state at -196 °Celsius, the boiling point of the nitrogen usually used for cooling.
For about thirty years, scientists have been investigating how the strong correlations - due to the resistance-free conductivity - can be maintained even at these - from a physical point of view - high temperatures without being limited in their function. To date, producing microprocessor with superconductors is starting to show some results; forming the foundation of some promising application in quantum technology, however the producing of microprocessors with high-temperature superconductors has been a major problem: Some of these materials are oxides, and any interaction with water molecules degrades their conductive properties. However, many of the chemical solutions used by technology companies in clean rooms to control silicon, for example, are based on water molecules, which would require significant manufacturing effort. In addition, interaction with oxygen also affects the properties of the superconductor. Its molecules, which are among the most volatile elements in nature, tend to interact anomalously with the material structure of the oxides at high temperatures and deforming them.
Specific stacking for suitable interfaces
In the Superpuddles Lab at Leibniz Institute for Solid State and Materials Research Dresden, the research team led by Dr. Nicola Poccia has now developed a technique for assembling thin cuprate crystals - as this type of ceramic superconductor is known - in such a way that the resulting structures demonstrate ideal properties for sensory applications and are also comparatively easy to control. The team found that suitable interfaces between the crystals are created when the specific stacking of the individual components performed in the process is carried out under cryogenic temperatures. This process prevents additional oxygen atoms from building into the structure of the superconductor, deforming it and thus damaging the interface between the individual " bricks". The researchers also did not just arrange the structures vertically, but aligned them at an angle to each other. In the tests, the structures were also encapsulated and exhibited significantly more stability than the plain configurations. A new equipment was set up in the laboratory specifically for this method. Simple circuits can be assembled here with the exclusion of water molecules and without the need for polymers or other chemicals that would degrade the properties of the high-temperature superconductor.
The improved investigation of these three-dimensional cuprate structures of a few tenths of a nanometer created in this way should also make it possible to design completely new circuits in the coming future. These could then not only be used to design new sensor technologies and for computing applications, but also enable scientists to get to the bottom of the mysterious phenomenon of high-temperature superconductivity not only theoretically, but also practically.
Original publication in Advanced Materials, 2023:
Dr. Nicola Poccia
Phone: +49 351 – 4659 527
Phone: +49 351 - 4659 249