Insulator-to-Metal Transition and Isotropic Gigantic Magnetoresistance in Layered Magnetic Semiconductors

TL;DR

This paper reports a layered magnetic semiconductor, GdPS, exhibiting an isotropic, gigantic negative magnetoresistance and a field-driven insulator-to-metal transition, driven by unique electronic interactions, promising for advanced spintronic applications.

Contribution

It introduces GdPS as a new material demonstrating isotropic magnetoresistance and an insulator-metal transition, highlighting the role of minimal spin-orbit coupling and strong exchange interactions.

Findings

GdPS exhibits isotropic gigantic negative magnetoresistance.

GdPS undergoes a field-driven insulator-to-metal transition.

The isotropic magnetoresistance is due to minimal spin-orbit coupling and strong f-d exchange.

Abstract

Magnetotransport, the response of electrical conduction to external magnetic field, acts as an important tool to reveal fundamental concepts behind exotic phenomena and plays a key role in enabling spintronic applications. Magnetotransport is generally sensitive to magnetic field orientations. In contrast, efficient and isotropic modulation of electronic transport, which is useful in technology applications such as omnidirectional sensing, is rarely seen, especially for pristine crystals. Here we propose a strategy to realize extremely strong modulation of electron conduction by magnetic field which is independent of field direction. GdPS, a layered antiferromagnetic semiconductor with resistivity anisotropies, supports a field-driven insulator-to-metal transition with a paradoxically isotropic gigantic negative magnetoresistance insensitive to magnetic field orientations. This isotropic magnetoresistance originates from the combined effects of a near-zero spin-orbit coupling of Gd3+-based half-filling f-electron system and the strong on-site f-d exchange coupling in Gd atoms. Our results not only provide a novel material system with extraordinary magnetotransport that offers a missing block for antiferromagnet-based ultrafast and efficient spintronic devices, but also demonstrate the key ingredients for designing magnetic materials with desired transport properties for advanced functionalities.