Spin-orbit-derived giant magnetoresistance in a layered magnetic semiconductor AgCrSe2

TL;DR

This paper reports a giant positive magnetoresistance in the layered magnetic semiconductor AgCrSe2, driven by spin-orbit coupling and Zeeman splitting, revealing new spintronic functionalities in 2D magnetic materials.

Contribution

It demonstrates the first observation of giant magnetoresistance in AgCrSe2 caused by SOC and Zeeman splitting, highlighting a new mechanism for magnetotransport in 2D magnetic semiconductors.

Findings

~400% positive magnetoresistance at critical carrier concentration

Magnetoresistance linked to effective carrier mass enhancement

First-principles calculations support SOC and Zeeman splitting effects

Abstract

Two-dimensional magnetic materials have recently attracted great interest due to their unique functions as the electric field control of a magnetic phase and the anomalous spin Hall effect. For such remarkable functions, a spin-orbit coupling (SOC) serves as an essential ingredient. Here we report a giant positive magnetoresistance in a layered magnetic semiconductor AgCrSe2, which is a manifestation of the subtle combination of the SOC and Zeeman-type spin splitting. When the carrier concentration approaches the critical value of 2.5\times10^18 cm^-3, a sizable positive magnetoresistance of ~400 % emerges upon the application of magnetic fields normal to the conducting layers. Based on the magneto-Seebeck effect and the first-principles calculations, the unconventional magnetoresistance is ascribable to the enhancement of effective carrier mass in the SOC induced J = 3/2 state, which is tuned to the Fermi level through the Zeeman splitting enhanced by the p-d coupling. This study demonstrates a new aspect of the SOC-derived magnetotransport in two-dimensional magnetic semiconductors, paving the way to novel spintronic functions.