Cr$_3$X$_4$ (X=Se, Te) monolayers as new platform to realize robust spin filter, spin diode and spin valve

TL;DR

This paper explores Cr$_3$X$_4$ (X=Se, Te) monolayers as promising materials for spintronic devices, demonstrating their ability to act as spin filters, diodes, and valves with notable effects like NDRE and high magnetoresistance.

Contribution

The study introduces Cr$_3$X$_4$ monolayers as new 2D materials capable of enabling multiple spintronic functionalities, including spin filtering, diode, and valve effects, with detailed transport property analysis.

Findings

Cr$_3$Te$_4$ monolayer exhibits spin filtering and dual spin diode effects.

Cr$_3$Se$_4$ monolayer functions as an effective spin valve.

Cr$_3$Se$_4$ device shows negative differential resistance and high magnetoresistance.

Abstract

Two-dimensional ferromagnetic (FM) half-metals are promising candidates for advanced spintronic devices with small-size and high-capacity. Motivated by recent report on controlling synthesis of FM Cr$_3$Te$_4$ nanosheet, herein, to explore the potential application in spintronics, we designed spintronic devices based on Cr$_3$X$_4$ (X=Se, Te) monolayers and investigated their spin transport properties. We found that Cr$_3$Te$_4$ monolayer based device shows spin filtering and dual spin diode effect when applying bias voltage, while Cr$_3$S$_4$ monolayer is an excellent platform to realize a spin valve. The different transport properties are primarily ascribed to the semiconducting spin channel, which is close to and away from the Fermi level in Cr$_3$Te$_4$ and Cr$_3$Se$_4$ monolayers, respectively. Interestingly, the current in monolayer Cr$_3$Se$_4$ based device also displays a negative differential resistance effect (NDRE) and a high magnetoresistance ratio (up to 2*10$^3$). Moreover, we found thermally induced spin filtering effect and NDRE in Cr$_3$Se$_4$ junction when applying temperature gradient instead of bias voltage. These theoretical findings highlight the potential of Cr$_3$X$_4$ (X=Se, Te) monolayers in spintronic applications and put forward realistic materials to realize nanosale spintronic device.