Strength Of Superconductivity Research Articles

Scalability of non-adiabatic effects in lithium-decorated graphene superconductor

The analysis is conducted to unveil how the non-adiabatic effects scale within the superconducting phase of lithium-decorated graphene . Based on the Eliashberg formalism it is shown that the non-adiabatic effects notably reduce essential superconducting parameters in and arise as a significant oppressor of the discussed phase. Moreover, non-adiabaticity is found to scale with the strength of superconductivity, proportionally to the phonon energy scale and inversely with respect to the electron-phonon coupling. These findings are partially in contrast to other theoretical studies and show that superconductivity in is more peculiar than previously anticipated. In this context, the guidelines for enhancing superconducting phase in and sibling materials are also proposed.

Scanning SQUID Imaging of Reduced Superconductivity Due to the Effect of Chiral Molecule Islands Adsorbed on Nb

AbstractUnconventional superconductivity was realized in systems comprising a monolayer of magnetic adatoms adsorbed on conventional superconductors, forming Shiba‐bands. Another approach to induce unconventional superconductivity and 2D Shiba‐bands was recently introduced, namely, by adsorbing chiral molecules (ChMs) on conventional superconductors, which act in a similar way to magnetic impurities as verified by conductance spectroscopy. However, the fundamental effect ChMs have on the strength of superconductivity has not yet been directly observed and mapped. In this work, local magnetic susceptometry is applied on heterostructures comprising islands of ChMs (α‐helix L‐polyalanine) monolayers adsorbed on Nb. It is found that the ChMs alter the superconducting landscape, resulting in spatially‐modulated weaker superconductivity. Surprisingly, the reduced diamagnetic response is located along the perimeter of the islands with respect to both their interior and the bare Nb. The authors suggest that topological edge‐states forming at the edges are the source of the reduced superconductivity, akin to the case of magnetic islands. The results pave new paths for the realization of topological‐superconductivity‐based devices with changing order parameter.

Superconductivity emerging from a stripe charge order in IrTe2 nanoflakes

Superconductivity in the vicinity of a competing electronic order often manifests itself with a superconducting dome, centered at a presumed quantum critical point in the phase diagram. This common feature, found in many unconventional superconductors, has supported a prevalent scenario in which fluctuations or partial melting of a parent order are essential for inducing or enhancing superconductivity. Here we present a contrary example, found in IrTe2 nanoflakes of which the superconducting dome is identified well inside the parent stripe charge ordering phase in the thickness-dependent phase diagram. The coexisting stripe charge order in IrTe2 nanoflakes significantly increases the out-of-plane coherence length and the coupling strength of superconductivity, in contrast to the doped bulk IrTe2. These findings clarify that the inherent instabilities of the parent stripe phase are sufficient to induce superconductivity in IrTe2 without its complete or partial melting. Our study highlights the thickness control as an effective means to unveil intrinsic phase diagrams of correlated van der Waals materials.

Nanoscale Patterning of Superconductivity

Researchers spatially vary the strength of superconductivity on a nanometer scale using a ferroelectric material on top.

Magnetization study of YBa2Cu3Oy high-temperature superconductors: The effect of copper depletion and silver addition

Meissner effect measurements were used to characterize the effect of copper depletion and silver substitution on the bulk superconducting properties of YBa2Cu3Oy. A strong copper composition dependence of superconductivity was observed: A 20% depletion of copper from the samples resulted in an 88% decrease in the strength of superconductivity in YBa2Cu3Oy as measured by the Meissner effect. Because flux trapping and field penetration were likely to be significant in the high-Tc materials, it was difficult to determine the volume fraction of superconducting material in the samples. Variations in the lattice constants were consistent with copper composition-induced disorder on the orthorhombic lattice which became more pseudocubic, i.e., a≂b=c/3, with copper depletion. The addition of silver had essentially no effect on superconductivity or the lattice constants of YBa2Cu3Oy.