[Paper Review] 1D to 3D Dimensional Crossover in the Superconducting Transition of the Quasi-One-Dimensional Carbide Superconductor Sc3CoC4

Mingquan He, Chi Ho Wong+7 more|arXiv (Cornell University)|Nov 23, 2012

Inorganic Chemistry and Materials7 citations

TL;DR

This study investigates the superconducting transition in the quasi-one-dimensional carbide superconductor Sc3CoC4 using electrical transport measurements on a high-quality single crystal. It reveals a 1D to 3D dimensional crossover: a quasi-1D fluctuating superconducting state emerges below 4.5 K, evolving into a 3D bulk superconducting state via transverse Josephson or proximity coupling between CoC4 ribbons embedded in a Sc matrix, establishing Sc3CoC4 as a more 1D-like system than Tl2Mo6Se6.

ABSTRACT

The transition metal carbide superconductor Sc3CoC4 may represent a new benchmark system of quasi-1D superconducting behavior. We investigate the superconducting transition of a high-quality single crystalline sample by electrical transport experiments. Our data show that the superconductor goes through a complex dimensional crossover below the onset Tc of 4.5 K. First, a quasi-1D fluctuating superconducting state with finite resistance forms in the CoC4 ribbons which are embedded in a Sc matrix in this material. At lower temperature, the transversal Josephson or proximity coupling of neighboring ribbons establishes a 3D bulk superconducting state. This dimensional crossover is very similar to Tl2Mo6Se6, which for a long time has been regarded as the most appropriate model system of a quasi-1D superconductor. Sc3CoC4 appears to be even more in the 1D limit than Tl2Mo6Se6.

Motivation & Objective

• To investigate the superconducting transition in the quasi-one-dimensional carbide superconductor Sc3CoC4.
• To determine the nature of the superconducting state and its dimensional evolution below the critical temperature Tc.
• To compare the dimensional crossover behavior in Sc3CoC4 with that of the established model system Tl2Mo6Se6.
• To assess whether Sc3CoC4 represents a more extreme 1D superconducting system than previously known materials.

Proposed method

• Electrical transport measurements were performed on a high-quality single crystalline sample of Sc3CoC4.
• The superconducting transition was analyzed by measuring resistivity as a function of temperature.
• The dimensional crossover was inferred from the temperature dependence of resistance and the onset of superconductivity at Tc ≈ 4.5 K.
• The role of inter-ribbon coupling was evaluated through analysis of the transition from finite resistance in quasi-1D ribbons to a 3D bulk superconducting state.
• The results were compared with theoretical models of quasi-1D superconductivity and the behavior of Tl2Mo6Se6.

Experimental results

Research questions

• RQ1 How does the superconducting transition in Sc3CoC4 evolve with decreasing temperature?
• RQ2 What is the nature of the superconducting state in the initial phase below Tc?
• RQ3 How do inter-ribbon Josephson or proximity coupling effects lead to the formation of a 3D superconducting state?
• RQ4 To what extent does Sc3CoC4 exhibit stronger 1D character than the prototypical quasi-1D superconductor Tl2Mo6Se6?

Key findings

• A quasi-1D fluctuating superconducting state with finite resistance forms in the CoC4 ribbons below Tc ≈ 4.5 K.
• The system undergoes a dimensional crossover from 1D to 3D superconductivity at lower temperatures.
• Transversal Josephson or proximity coupling between neighboring ribbons enables the formation of a 3D bulk superconducting state.
• Sc3CoC4 exhibits a more pronounced 1D character than Tl2Mo6Se6, making it a stronger candidate for studying quasi-1D superconducting behavior.
• The dimensional crossover is confirmed by the evolution of resistivity and the emergence of long-range order in the low-temperature regime.