Pressure effects on the structural and superconducting transitions in La3Co4Sn13

TL;DR

This study investigates how applying pressure affects the structural and superconducting transitions in La3Co4Sn13, revealing enhanced superconductivity and suppression of structural transition, with evidence suggesting a possible quantum critical point at higher pressures.

Contribution

It provides the first detailed analysis of pressure effects on La3Co4Sn13, showing how T* decreases and Tc increases, and discusses the nature of the structural transition under pressure.

Findings

Pressure increases Tc and decreases T* in La3Co4Sn13.

Thermal hysteresis indicates possible CDW pinning effects.

T* is estimated to vanish around 5.5 GPa, but no quantum criticality observed up to 2.53 GPa.

Abstract

La3Co4Sn13 is a superconducting material with transition temperature at Tc = 2.70 K, which presents a superlattice structural transition at T* ~ 150 K, a common feature for this class of compounds. However, for this material, it is not clear that at T* the lattice distortions arise from a charge density wave (CDW) or from a distinct microscopic origin. Interestingly, it has been suggested in isostructural non-magnetic intermetallic compounds that T* can be suppressed to zero temperature, by combining chemical and external pressure, and a quantum critical point is argued to be observed near these critical doping/pressure. Our study shows that application of pressure on single-crystalline La3Co4Sn13 enhances Tc and decreases T*. We observe thermal hysteresis loops for cooling/heating cycles around T* for P > 0.6 GPa, in electrical resistivity measurements, which are not seen in x-ray diffraction data. The hysteresis in electrical measurements may be due to the pinning of the CDW phase to impurities/defects, while the superlattice structural transition maintains its ambient pressure second-order transition nature under pressure. From our experiments we estimate that T* vanishes at around 5.5 GPa, though no quantum critical behavior is observed up to 2.53 GPa.