Anisotropic superconductivity in layered LaSb$_2$: the role of phase fluctuations

TL;DR

This study investigates the anisotropic superconducting properties of LaSb$_2$, revealing a broad transition influenced by phase fluctuations and a pressure-induced crossover from 2D to 3D behavior.

Contribution

It provides new insights into the role of phase fluctuations and dimensional crossover in the superconductivity of LaSb$_2$, a highly anisotropic layered compound.

Findings

Superconducting transition is broad and phase fluctuation limited at ambient pressure.

Hydrostatic pressure reduces anisotropy and transition width, indicating a 2D to 3D crossover.

Phase fluctuations are observed at temperatures much higher than the critical temperature.

Abstract

We present magnetic susceptibility and electrical transport measurements of the highly anisotropic compound LaSb$_2$ observing a very broad transition into a clean, consistent with type-I, superconducting state with distinct features of 2 dimensionality. Application of hydrostatic pressure induces a 2- to 3-dimensional crossover evidenced by a reduced anisotropy and transition width. The superconducting transition appears phase fluctuation limited at ambient pressure with fluctuations observed for temperatures greater than 8 times the superconducting critical temperature.