Is a doped 'Kondo' insulator different from doped Silicon?

TL;DR

This study investigates the metal-insulator transition in FeSi doped with Al, revealing similarities to doped silicon but with significantly enhanced quasiparticle mass, and confirms the applicability of disordered Fermi Liquid theory at low temperatures.

Contribution

It demonstrates that doping FeSi induces a metal-insulator transition with properties akin to doped silicon, but with notable differences such as increased quasiparticle mass.

Findings

Metal-insulator transition observed in FeSi with Al doping.

Doped FeSi shows metallic behavior similar to Si:P.

Low-temperature conductivity aligns with disordered Fermi Liquid theory.

Abstract

We have observed the metal-insulator transition in the strongly correlated insulator FeSi with the chemical substitution of Al at the Si site. The magnetic susceptibility, heat capacity, and field dependent conductivity are measured for Al concentrations ranging from 0 to 0.08. For concentrations greater than 0.01 we find metallic properties quantitatively similar to those measured in Si:P with the exception of a greatly enhanced quasiparticle mass. Below 2 K the temperature and field dependent conductivity can be completely described by the theory of disordered Fermi Liquids.