Topological Tunneling Magnetoresistance Driven by Type-II Weyl-Like States in the Room-Temperature Half-Metal Mn2PC Monolayer

TL;DR

This paper predicts that the Mn2PC monolayer is a room-temperature ferromagnetic half-metal with topologically non-trivial Weyl-like states, enabling a novel topological tunneling magnetoresistance effect suitable for spintronic applications.

Contribution

It introduces the Mn2PC monolayer as a new room-temperature topological half-metal with Weyl-like states and proposes a topological tunneling magnetoresistance device based on its properties.

Findings

Mn2PC monolayer is a ferromagnetic half-metal with T_C of 554 K.

Presence of type-II Weyl-like crossings at the Fermi level.

Proposed topological tunneling magnetoresistance device with giant MR ratio.

Abstract

We predict the tetragonal Mn2PC monolayer to be a room-temperature ferromagnetic half-metal with a Curie temperature of 554 K. The spin-up channel hosts type-II Weyl-like crossings at the Fermi level with highly anisotropic band dispersion, whereas the spin-down channel is a wide-gap semiconductor. Topological edge states obtained from tight-binding calculations confirm the non-trivial bulk topology. Spin-orbit coupling opens a small gap of 11.2 meV at the Weyl-like crossings, generating pronounced Berry curvature and a sizable anomalous Hall conductivity near the Fermi level. Based on these properties, we propose topological tunneling magnetoresistance in a Mn2PC-based magnetic tunnel junction: the parallel configuration conducts through fully spin-polarized Weyl-like carriers, while the antiparallel configuration is suppressed by the half-metallic gap, yielding a giant magnetoresistance ratio. The concurrent anomalous Hall effect in the conducting state provides an experimentally accessible signature of the topological carriers. These results identify the Mn2PC monolayer as a promising platform for room-temperature topological spintronic devices.