Quantum criticality and multiple crossing points in the magnetoresistance of thin TiN-films

TL;DR

This study investigates the magnetoresistance behavior of a TiN thin-film near the superconductor-insulator transition, revealing multiple crossing points indicative of complex quantum critical phenomena.

Contribution

The paper reports the observation of three distinct crossing points in magnetoresistance isotherms, providing insights into quantum phase transitions in disordered superconducting films.

Findings

Identification of three crossing points at different magnetic fields

Each crossing point corresponds to a plateau in resistance

Estimates for critical exponents z and ν

Abstract

We have measured $R(T,B)$ of a TiN thin-film very close to the disorder-driven superconductor-insulator transition but still superconducting at zero field and low temperatures. In a magnetic field we find three distinct crossing point of the magnetoresistance isotherms occur at magnetic fields $B_{cX}$ in three different temperature regions. Each crossing point in $R(T,B)$ corresponds to a plateau in $R(T,B_{cX})$. We systematically study the evolution of these crossing point near the disorder-induced superconductor/insulator transition, identify the most promising candidate for a quantum phase transition, and provide estimates for the two critical exponents $z$ and $\nu$.