Insulator-to-metal phase transition in Yb-based Kondo insulators

TL;DR

This paper models Yb-based Kondo insulators using the periodic Anderson lattice, showing that reducing hybridization can induce an insulator-to-metal transition with observable Fermi pockets.

Contribution

It introduces a theoretical framework for the insulator-to-metal transition in Yb-based Kondo insulators via hybridization differences in the CEF split states.

Findings

Decreasing hybridization difference induces transition

Metallic phase has Fermi pockets

Pressure can experimentally realize transition

Abstract

The periodic Anderson lattice model for the crystalline electric field (CEF)split 4f quartet states is used to describe the Yb-based Kondo insulators/semiconductors. In the slave-boson mean-field approximation, we derive the hybridized quasiparticle bands, and find that decreasing the hybridization difference of the two CEF quartets may induce an insulator-to-metal phase transition. The resulting metallic phase has a hole and an electron Fermi pockets. Such a phase transition may be realized experimentally by applying pressure, reducing the difference in hybridization of the two CEF quartets.