Current-driven magnetic resistance in van der Waals spin-filter antiferromagnetic tunnel junctions with MnBi$_2$Te$_4$

TL;DR

This paper theoretically investigates MnBi$_2$Te$_4$ van der Waals antiferromagnetic tunnel junctions, demonstrating how device length, bias voltage, and boron nitride layers can significantly enhance tunneling magneto-resistance for spintronics applications.

Contribution

It introduces a theoretical model showing how to manipulate TMR in MnBi$_2$Te$_4$ devices using structural and bias controls, with a focus on the impact of boron nitride layers.

Findings

TMR can reach up to 3690% with bias voltage and device engineering.

Boron nitride layers significantly enhance TMR by suppressing specific spin channels.

Structural and magnetic configurations critically influence spin-polarized transport.

Abstract

The field of 2D magnetic materials has paved the way for the development of spintronics and nanodevices with new functionalities. Utilizing antiferromagnetic materials, in addition to layered van der Waals (vdW) ferromagnetic materials, has garnered significant interest. In this work, we present a theoretical investigation of the behavior of MnBi$_2$Te$_4$ devices based on the non-equilibrium Green's function method. Our results show that the current-voltage (I-V) characteristics can be influenced significantly by controlling the length of the device and bias voltage and thus allow us to manipulate the tunneling magneto-resistance (TMR) with an external bias voltage. This can be further influenced by the presence of the boron nitride layer which shows significantly enhanced TMR by selectively suppressing specific spin channels for different magnetic configurations. By exploiting this mechanism, the observed TMR value reaches up to 3690\%, which can be attributed to the spin-polarized transmission channel and the projected local density of states. Our findings on the influence of structural and magnetic configurations on the spin-polarized transport properties and TMR ratios give the potential implementation of antiferromagnetic vdW layered materials in ultrathin spintronics.