Field-induced quantum critical point in CeCoIn_5

TL;DR

This study investigates the resistivity of CeCoIn_5 at ultra-low temperatures and high magnetic fields, revealing a field-induced quantum critical point at the superconducting upper critical field, characterized by non-Fermi liquid to Fermi liquid transition.

Contribution

It provides experimental evidence for a new quantum critical point induced by magnetic field in CeCoIn_5, coinciding with the superconducting critical field.

Findings

Suppression of non-Fermi liquid behavior with increasing magnetic field

Development of Fermi liquid state with T^2 dependence of resistivity

Critical behavior of the T^2 coefficient with an exponent of ~4/3

Abstract

The resistivity of CeCoIn_5 was measured down to 20 mK in magnetic fields of up to 16 T. With increasing field, we observe a suppression of the non-Fermi liquid behavior, rho~T, and the development of a Fermi liquid state, with its characteristic rho=rho_0+AT^2 dependence. The field dependence of the T^2 coefficient shows critical behavior with an exponent of ~4/3. This is evidence for a new field-induced quantum critical point, occuring in this case at a critical field which coincides with the superconducting upper critical field H_c2.