Resistivity of Mn$_{1-x}$Fe$_x$Si single crystals: Evidence for quantum critical behavior

TL;DR

This study investigates how Fe doping in MnSi single crystals affects resistivity and reveals evidence of a quantum critical point characterized by non-Fermi-liquid behavior near high Fe concentrations.

Contribution

It provides experimental evidence for quantum critical behavior in Mn$_{1-x}$Fe$_x$Si through resistivity measurements across various doping levels.

Findings

Fe doping suppresses magnetic order temperature to below 2K at x=0.15

Resistivity temperature dependence remains stable despite increased residual resistivity

Evidence of non-Fermi-liquid behavior near x=0.15 indicating a quantum critical point

Abstract

Resistivity measurements have been made on Mn$_{1-x}$Fe$_x$Si single crystals between 2 and 300K for $x$ = 0, 0.05, 0.08, 0.12 and 0.15. Fe doping is found to depress the magnetic ordering temperature from 30K for $x$ = 0 to below 2K for $x$ = 0.15. Although Fe doping results in a large increase of the low-temperature residual resistivity, the temperature dependence of the resistivity above the magnetic transition remains practically unaffected by increasing Fe content. An analysis of the temperature derivative of the resistivity provides strong evidence for the existence of a non-Fermi-liquid ground state near $x$ = 0.15 and thus for a quantum critical point tuned by Fe content.