Skip to main content

High pressure orders electrons

High pressure orders electrons :

Researchers examine competing states in high-temperature superconductors.

To apply controlled pressure to their microscopic superconducting sample (graphics), researchers use sensitive brackets with actuators based on the piezoelectric effect.

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 researchers report on it in the Science journal.
Transporting current without losses -- superconductors make it possible but only below a certain critical temperature. Conventional superconductors need to be cooled down to almost absolute zero -- minus 273 degrees Celsius -- and even the so-called high-temperature superconductors still need temperatures of around minus 200 degrees Celsius to transport current without resistance. Despite this, superconductors are already used in various areas (superconducting magnets, frequency filters, high density power lines). To develop superconductors that work at even higher temperatures -- possibly up to room temperature -- and therefore significantly contribute to an efficient energy supply, electronic states 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. In addition to IFP at KIT, the Max Planck Institute for Solid State Research in Stuttgart, the Max Planck Institute for Chemical Physics of Solids in Dresden, the European Synchrotron Radiation Facility (ESRF) in Grenoble, France, and the Universidad Nacional de la Plata in Argentina took part in the study. The results are presented in the Science journal.
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 allows to study its relationship to superconductivity using x-ray scattering, as the researchers from Karlsruhe, Stuttgart, Dresden, Grenoble and La Plata discovered in their work. They have in particular been able to identified strong anomalies of the lattice excitation conneted 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 superconductitivity" explains 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."

Comments

Post a Comment

Popular posts from this blog

Size matters: New data reveals cell size sparks genome awakening in embryos

Transitions are a hallmark of life. When dormant plants flower in the spring or when a young adult strikes out on their own, there is a shift in control. Similarly, there is a transition during early development when an embryo undergoes biochemical changes, switching from being controlled by maternal molecules to being governed by its own genome. For the first time, a team from the Perelman School of Medicine at the University of Pennsylvania found in an embryo that activation of its genome does not happen all at once, instead it follows a specific pattern controlled primarily by the various sizes of its cells. The researchers published their results this week as the cover story in  Developmental Cell . In an early embryo undergoing cell division, maternally loaded RNA and proteins regulate the cell cycle. The genomes of the zygote -- a term for the fertilized egg -- are initially in sleep mode. However, at a point in the early life of the embryo, these zygotic nuclei "wake...
Post a Comment
Read more

Home births as safe as hospital births: International study suggests

A large international study led by McMaster University shows that low risk pregnant women who intend to give birth at home have no increased chance of the baby's perinatal or neonatal death compared to other low risk women who intend to give birth in a hospital. The results have been published by  The Lancet 's  EClinicalMedicine  journal. "More women in well-resourced countries are choosing birth at home, but concerns have persisted about their safety," said Eileen Hutton, professor emeritus of obstetrics and gynecology at McMaster, founding director of the McMaster Midwifery Research Centre and first author of the paper. "This research clearly demonstrates the risk is no different when the birth is intended to be at home or in hospital." The study examined the safety of place of birth by reporting on the risk of death at the time of birth or within the first four weeks, and found no clinically important or statistically different risk between home...
Post a Comment
Read more

Molecular adlayer produced by dissolving water-insoluble nanographene in water

Molecular adlayer produced by dissolving water-insoluble nanographene in water : "Nanographene incorporated micelle capsules" can be prepared by simply pulverizing and mixing nanographene with amphiphilic V-shaped anthracene molecules in water at room temperature. Even though nanographene is insoluble in water and organic solvents, Kumamoto University (KU) and Tokyo Institute of Technology (Tokyo Tech) researchers have found a way to dissolve it in water. Using "molecular containers" that encapsulate water-insoluble molecules, the researchers developed a formation procedure for a nanographene adlayer, a layer that chemically interacts with the underlying substance, by just mixing the molecular containers and nanographene together in water. The method is expected to be useful for the fabrication and analysis of next-generation functional nanomaterials. Graphene is a single layer of carbon atoms arranged in sheet form. It is lighter than metal wit...
Post a Comment
Read more