Field-induced Metal-Insulator Transition in $\beta $-EuP$_3$

TL;DR

This paper reports a magnetic-field-induced metal-insulator transition in $eta$-EuP$_3$, accompanied by colossal magnetoresistance, driven by a transition from an insulator to a spin-polarized topological semimetal.

Contribution

It presents the first observation of a magnetic-field-driven MIT in $eta$-EuP$_3$, revealing a new mechanism involving spin configuration and spin-orbit coupling.

Findings

Resistance drops billionfold at 2 K in less than 3 T

Transition from insulator to topological semimetal

Spin configuration and SOC are crucial

Abstract

Metal-insulator transition (MIT) is one of the most conspicuous phenomena in correlated electron systems. However such transition has rarely been induced by an external magnetic field as the field scale is normally too small compared with the charge gap. In this paper we present the observation of a magnetic-field-driven MIT in a magnetic semiconductor $\beta $-EuP$_3$. Concomitantly, we found a colossal magnetoresistance (CMR) in an extreme way: the resistance drops billionfold at 2 kelvins in a magnetic field less than 3 teslas. We ascribe this striking MIT as a field-driven transition from an antiferromagnetic and paramagnetic insulator to a spin-polarized topological semimetal, in which the spin configuration of $\mathrm{Eu^{2+}}$ cations and spin-orbital coupling (SOC) play a crucial role. As a phosphorene-bearing compound whose electrical properties can be controlled by the application of field, $\beta $-EuP$_3$ may serve as a tantalizing material in the basic research and even future electronics.