Spin direction controlled electronic band structure in two dimensional ferromagnetic CrI3

TL;DR

This paper theoretically demonstrates that changing the magnetization direction in 2D ferromagnetic CrI3 significantly alters its electronic band structure, enabling control over optical and electronic properties for spintronics.

Contribution

It reveals a giant magneto band-structure effect in CrI3, showing how magnetization orientation influences bandgap, Fermi surface, and topological states, which is novel for 2D ferromagnets.

Findings

Out-of-plane to in-plane magnetization causes a direct-to-indirect bandgap transition.

Magnetization direction significantly alters the Fermi surface and magnetoresistance.

Spin reorientation modifies the topological states in CrI3.

Abstract

Manipulating physical properties using the spin degree of freedom constitutes a major part of modern condensed matter physics and is very important for spintronics devices. Using the newly discovered two dimensional van der Waals ferromagnetic CrI3 as a prototypic material, we theoretically demonstrated a giant magneto band-structure (GMB) effect whereby a change of magnetization direction significantly modifies the electronic band structure. Our density functional theory calculations and model analysis reveal that rotating the magnetic moment of CrI3 from out-of-plane to in-plane causes a direct-to-indirect bandgap transition, inducing a magnetic field controlled photoluminescence. Moreover, our results show a significant change of Fermi surface with different magnetization directions, giving rise to giant anisotropic magnetoresistance. Additionally, the spin reorientation is found to modify the topological states. Given that a variety of properties are determined by band structures, our predicted GMB effect in CrI3 opens a new paradigm for spintronics applications.