Electronic, Magnetic and Vibrational Properties of Single Layer Aluminum Oxide

TL;DR

This study uses first-principles calculations to explore the structural, magnetic, vibrational, and electronic properties of single-layer aluminum oxide, revealing its potential for nanoscale device applications due to its stability and magnetic features.

Contribution

It provides the first detailed theoretical analysis of 1T'-AlO2's properties, including magnetic behavior, vibrational spectrum, and defect robustness, highlighting its application potential.

Findings

1T'-AlO2 forms a distorted octahedral structure.

Surface O atoms induce magnetic behavior.

Both FM and AFM phases are semiconductors.

Abstract

The structural, magnetic, vibrational and electronic properties of single layer aluminum oxide (AlO2) are investigated by performing state-of-the-art first-principles calculations. Total energy optimization and phonon calculations reveal that aluminum oxide forms a distorted octahedral structure (1T'-AlO2) in its single layer limit. It is also shown that surfaces of 1T'-AlO2 display magnetic behavior originating from the O atoms. While the ferromagnetic (FM) state is the most favorable magnetic order for 1T'-AlO2, transformation to a dynamically stable antiferromagnetic (AFM) state upon a slight distortion in the crystal structure is also possible. It is also shown that Raman activities (350-400 cm^-1) obtained from the vibrational spectrum can be utilized to distinguish the possible magnetic phases of the crystal structure. Electronically, both FM and the AFM phases are semiconductors with an indirect band gap and they can form a type-III vdW heterojunction with graphene-like ultra-thin materials. Moreover, it is predicted that presence of oxygen defects that inevitably occur during synthesis and production do not alter the magnetic state, even at high vacancy density. Apparently, ultra-thin 1T'-AlO2 with its stable crystal structure, semiconducting nature and robust magnetic state is a quite promising material for nanoscale device applications.