Anomalous Properties in the Normal and Superconducting States of LaRu$_3$Si$_2$

TL;DR

This study investigates the anomalous thermal and superconducting properties of LaRu$_3$Si$_2$, revealing deviations from standard models and evidence of strong electron correlations and superconducting fluctuations.

Contribution

It reports novel specific heat behaviors and fluctuation effects in LaRu$_3$Si$_2$, highlighting unconventional superconducting characteristics.

Findings

Normal state specific heat deviates from Debye model

Strong superconducting fluctuations observed

Non-linear quasiparticle density of states dependence

Abstract

Superconductivity in LaRu$_3$Si$_2$ with the honeycomb structure of Ru atoms has been investigated. It is found that the normal state specific heat C/T exhibits a deviation from the Debye model down to the lowest temperature. A relation $C/T = \gamma_n+\beta T^2-ATlnT$ which concerns the electron correlations can fit the data very well. The suppression to the superconductivity by the magnetic field is not the mean-field like, which is associated well with the observation of strong superconducting fluctuations. The field dependence of the induced quasiparticle density of states measured by the low temperature specific heat shows a non-linear feature, indicating the significant contributions given by the delocalized quasiparticles.