High-Performance Nonvolatile Spin FETs from 2D Metallic Ferromagnetic and Ferroelectric Multiferroic Heterostructure

TL;DR

This paper proposes a novel 2D heterostructure-based spin FET that uses ferroelectric polarization to switch between metallic and semiconducting states, achieving high on/off ratios and spin polarization for advanced spintronics.

Contribution

It introduces an interface effect approach to convert inherently metallic 2D magnetic materials into functional states for spin FETs, demonstrated through DFT and NEGF calculations.

Findings

On/off current ratio exceeds 50 million percent.

Nearly 100% spin-polarized current achieved.

Current density up to 6500 μA/μm at low bias.

Abstract

All-electric-controlled nonvolatile spin field-effect transistors (SFETs) based on two-dimensional (2D) multiferroic van der Waals (vdW) heterostructures hold great promise for advanced spintronics applications. However, their performance is hindered by the limited availability of 2D magnetic materials that can switch effectively between metallic and semiconducting states with sizable bandgaps controlled by ferroelectric polarization. Most studies have focused on materials that are naturally semiconducting, achieving a metallic state by modifying the ferroelectric polarization. In this work, we introduce an innovative approach that uses interface effects to convert inherently metallic 2D magnetic materials into half-metals and induce half-semiconducting behavior through changes in ferroelectric polarization. Density functional theory (DFT) calculations on the CrPS3/Sc2CO2 heterostructure demonstrate that the ferroelectric polarization of Sc2CO2 monolayers can adjust the electronic structure of CrPS3, enabling a switch from half-metallic to half-semiconducting states. Building on these insights, we designed a nonvolatile SFET and analyzed its transport properties using the nonequilibrium Green's function (NEGF) method combined with DFT. Our results show that reversing the ferroelectric polarization achieves an on/off current ratio exceeding 5000000%, and the heterostructure generates nearly 100% spin-polarized current with a current density of up to 6500 {\mu}A/{\mu}m at bias voltage below 0.2 V. These findings highlight a promising pathway for developing high-performance SFETs that surpass existing 2D heterojunction materials.