By Josh Perry, Editor [email protected]
Researchers at the Karlsruhe (Germany) Institute of Technology (KIT) used high-resolution inelastic X-Ray scattering to discover that high uniaxial pressure creates a long-range charge order that competes with superconductivity, according to a report from the institute.
To apply controlled pressure to their microscopic superconducting sample (graphics), researchers use sensitive brackets with actuators based on the piezoelectric effect. (KIT)
This study helps scientists get a better understanding of the fundamentals behind the electronic states and processes of superconducting materials by demonstrating that uniaxial pressure can help tune the competing states in high-temperature superconductors.
“Using high-resolution inelastic x-ray scattering,” the article explained, “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 a charge ordered state, the electrons form stripe-shaped nanostructures. The researchers were able to create the state through pressure rather than through magnetic fields and were able to get a new understanding of the behavior of electrons in these materials.
The research was recently published in Science. The abstract read:
“Cuprates exhibit antiferromagnetic, charge density wave (CDW), and high-temperature superconducting ground states that can be tuned by means of doping and external magnetic fields. However, disorder generated by these tuning methods complicates the interpretation of such experiments.
“Here, we report a high-resolution inelastic x-ray scattering study of the high-temperature superconductor YBa2Cu3O6.67 under uniaxial stress, and we show that a three-dimensional long-range-ordered CDW state can be induced through pressure along the a axis, in the absence of magnetic fields. A pronounced softening of an optical phonon mode is associated with the CDW transition. The amplitude of the CDW is suppressed below the superconducting transition temperature, indicating competition with superconductivity.
“The results provide insights into the normal-state properties of cuprates and illustrate the potential of uniaxial-pressure control of competing orders in quantum materials.”
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