Nodal Superconducting Order Parameter and Thermodynamic Phase Diagram of (TMTSF)2ClO4

TL;DR

This study maps the nodal superconducting gap structure and thermodynamic phase diagrams of (TMTSF)2ClO4, revealing evidence of nodal spin-singlet superconductivity in a quasi-one-dimensional organic superconductor.

Contribution

First to determine the nodal gap structure in (TMTSF)2ClO4 using field-angle-resolved calorimetry, advancing understanding of its unconventional superconductivity.

Findings

Mapped the nodal gap structure in (TMTSF)2ClO4.

Obtained thermodynamic phase diagrams for all principal field directions.

Provided evidence supporting nodal spin-singlet pairing.

Abstract

The organic materials (TMTSF)2X are unique unconventional superconductors with archetypal quasi-one-dimensional (Q1D) electronic structures. Here, based on our comprehensive field-angle-resolved calorimetry of (TMTSF)2ClO4, we succeeded in mapping the nodal gap structure for the first time in Q1D systems, by discriminating between the Fermi wavevectors and Fermi velocities. In addition, the thermodynamic phase diagrams of (TMTSF)2ClO4 for all principal field directions are obtained. These findings, providing strong evidence of nodal spin-singlet superconductivity, serves as solid bases for further elucidation of anomalous superconducting phenomena in (TMTSF)2X.