Anomalous transverse resistance in 122-type iron-based superconductors

Area of Science:

• Condensed Matter Physics
• Materials Science
• Superconductivity

Background:

• Understanding the transition to superconductivity is crucial.
• Transverse resistance measurements offer insights into superconducting properties.

Purpose of the Study:

• Investigate the in-plane transverse resistance of Ba$_{0.5}$K$_{0.5}$Fe$_{2}$As$_{2}$ (BKFA) superconductors.
• Explore the origins of anomalous transverse resistance observed near the superconducting transition.

Main Methods:

• Fabrication of ultra-thin micro-bridges from optimally doped single crystals of BKFA.
• Measurement of in-plane transverse resistance at varying temperatures.
• Introduction of magnetic and nonmagnetic impurities to study their effect on the anomalous resistance.

Main Results:

• An anomalous transverse resistance was observed in BKFA superconductors around the superconducting transition temperature.
• This anomaly persisted even in the absence of magnetic order or structural distortion in optimally doped samples.
• The anomalous transverse resistance was significantly enhanced by the substitution of impurities.

Conclusions:

• The observed anomalous transverse resistance is not directly linked to magnetic order or structural distortions in optimally doped BKFA.
• Anisotropic scattering or the superconducting electronic nematic state are potential contributing factors to the phenomenon.
• Further research is needed to fully elucidate the underlying mechanisms of this anomalous transverse resistance.