Origin of Superconductivity in High-Temperature Copper Oxide Superconductors
Context: In a recent study associate Professor and his team from Okayama University, Japan, explored the source of high-temperature superconductivity in cuprates’ pseudogap state using an innovative meth
Superconductors are materials that conduct electricity with zero resistance when cooled to a specific temperature, known as the critical temperature.
- They have numerous applications, including power grids, maglev trains, and medical imaging.
- High-temperature superconductors (critical temperatures higher than conventional superconductors) hold significant potential for advancing various technologies.
- A class of HTS, copper oxides or cuprates, exhibits superconductivity through doping.
- In the low-doped state, a pseudogap opens. This pseudogap is considered a potential factor in the origin of superconductivity in these materials.
Key Highlights:
- They found a long-range charge density wave (CDW) order in optimally doped Bi2201 induced by a unique piezo-driven uniaxial strain cell, intentionally disrupting the crystal symmetry of the CuO2 plane.
- They employed nuclear magnetic resonance (NMR) to observe how the electronic structure of optimally doped Bi2201 superconductor responded to applied uniaxial compressive and tensile strains.
- The study found that when the strain reached 0.15%, there was a notable transformation in the material: the short-range CDW order transitioned into a long-range CDW order.
Implications:
- Increasing strain not only suppressed superconductivity but also enhanced the long-range charge density wave (CDW) order, indicating the coexistence of both phenomena.
- These findings suggest that a hidden long-range CDW order exists in the pseudogap state of cuprates, extending beyond the low-doped regime, and becomes visible under strain.
Challenging Conventional Theories: The findings challenge the traditional belief that magnetism is the primary driver of superconductivity in cuprates. This opens doors for new theoretical models.
Previous studies have revealed a long-range charge density wave (CDW) order in the low-doped regime of cuprates, which breaks the crystal symmetry of the copper oxide (CuO2) plane.
- CDW is a repeating wave-like pattern of electrons that affects the material’s conductivity.
- This symmetry breaking is significant, as superconductivity is known to arise inside or near symmetry-broken states.
- In the bismuth-based cuprate superconductor, Bi2Sr2-xLaxCuO6+δ (Bi2201), strong magnetic fields have been shown to induce a long-range symmetry-breaking CDW order. The exact role of these phenomena in the occurrence of superconductivity in cuprates remains unknown.
Pathways to Practical Applications: Unveiling the way for the development of more practical superconducting materials.
- High-temperature superconductors hold significant potential for lossless power transmission and storage, making substantial contributions to energy conservation and the pursuit of carbon neutrality.
- The application of superconductors in MRI technology has the potential to reduce costs and enhance accessibility to advanced medical imaging.
- Uniaxial Strain for Future Studies: The importance of uniaxial strain as a valuable tool for exploring superconductivity in cuprates and similar materials.
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