Pressure-induced and Composition-induced Structural Quantum Phase Transition in the Cubic Superconductor (Sr/Ca)_3Ir_4Sn_{13}

TL;DR

This study reveals a pressure- and composition-induced quantum phase transition in a cubic superconductor, linking structural changes to charge density waves and superconductivity, providing insights into quantum critical phenomena.

Contribution

It demonstrates the suppression of a superlattice transition to zero temperature through combined pressure, enabling the study of quantum phase transitions in a cubic charge density wave system.

Findings

Superlattice transition temperature T* can be tuned to zero with pressure and composition.

Structural transition is linked to charge density wave formation.

Interplay between quantum criticality and superconductivity is observed.

Abstract

We show that the quasi-skutterudite superconductor Sr_3Ir_4Sn_{13} undergoes a structural transition from a simple cubic parent structure, the I-phase, to a superlattice variant, the I'-phase, which has a lattice parameter twice that of the high temperature phase. We argue that the superlattice distortion is associated with a charge density wave transition of the conduction electron system and demonstrate that the superlattice transition temperature T* can be suppressed to zero by combining chemical and physical pressure. This enables the first comprehensive investigation of a superlattice quantum phase transition and its interplay with superconductivity in a cubic charge density wave system.