Quantum fluctuations-driven Melting Transitions in Two-dimensional Superconductors

TL;DR

This paper investigates how quantum fluctuations cause vortex lattice melting in 2D superconductors at near-zero temperatures, linking this transition to the emergence of anomalous metallic states.

Contribution

It demonstrates quantum fluctuation-driven vortex melting in 2D superconductors and connects this to the anomalous metal phase, providing a new framework for understanding quantum phase transitions.

Findings

Quantum fluctuations induce vortex lattice melting near zero temperature.

The anomalous metal arises from quantum melting of vortex solids.

Results are consistent across various 2D superconductors.

Abstract

Quantum fluctuations are pivotal in driving quantum phase transitions, exemplified by the quantum melting of Wigner crystals into Fermi liquids in electron systems. However, their impact on superconducting systems near zero temperature, particularly in the superconductor-insulator/metal transition, remains poorly understood. In this study, through electric transport measurements on the two-dimensional (2D) superconductor (SnS)1.17NbS2, we demonstrate that quantum fluctuations induce vortex displacement from their mean position, leading to the quantum melting of vortex solid near zero temperature. Quantitative analysis reveals the magnetic field-induced anomalous metal originates from this quantum melting transition, with energy dissipation governed by quantum fluctuations-driven vortex displacements. Remarkably, further extending this analysis to various 2D superconductors yields the same results, and many properties of anomalous metal can be qualitatively understood within the framework of quantum melting. The connection between the quantum melting of vortex solids and dissipative anomalous metal opens a novel pathway towards understanding quantum phase transitions through vortex dynamics, providing new insights on both fields.