Investigation of vacancy defects and substitutional doping in AlSb monolayer with double layer honeycomb structure: a first-principles calculation

The experimental knowledge of the AlSb monolayer with double layer honeycomb structure is largely based on the recent publication (Le Qin et al 2021 ACS Nano 15 8184), where this monolayer was recently synthesized. Therefore, the aim of our research is to consequently explore the effects of substitutional doping and vacancy point defects on the electronic and magnetic properties of the novel hexagonal AlSb monolayer. Besides experimental reports, the phonon band structure and cohesive energy calculations confirm the stability of the AlSb monolayer. Its direct bandgap has been estimated to be 0.9 eV via the hybrid functional method, which is smaller than the value of 1.6 eV of bulk material. The majority of vacancy defects and substitutional dopants change the electronic properties of the AlSb monolayer from semiconducting to metallic. Moreover, the Mg-Sb impurity has demonstrated the addition of ferromagnetic behavior to the material. It is revealed through the calculation of formation energy that in Al-rich conditions, the vacant site of V-Sb is the most stable, while in Sb-rich circumstances the point defect of V-Al gets the title. The formation energy has also been calculated for the substitutional dopants, showing relative stability of the defected structures. We undertook this theoretical study to inspire many experimentalists to focus their efforts on AlSb monolayer growth incorporating different impurities. It has been shown here that defect engineering is a powerful tool to tune the properties of novel AlSb two-dimensional monolayer for advanced nanoelectronic applications.

Automated summary

This study explores the effects of defect engineering on the electronic and magnetic properties of the AlSb monolayer. Experimental reports, phonon band structure calculations, and cohesive energy calculations confirm the stability of the AlSb monolayer and reveal that substitutional doping and vacancy defects can change its electronic properties from semiconducting to metallic. Additionally, the introduction of Mg-Sb impurity adds ferromagnetic behavior to the material. Formation energy calculations show that the stability of vacancy defects differs under different conditions. This theoretical study aims to inspire experimentalists to focus on the growth of AlSb monolayers with different impurities, as defect engineering is a powerful tool to tune the properties of these novel two-dimensional materials for advanced nanoelectronic applications.