Issue 25, 2024

Defect effects on the electronic, valley, and magnetic properties of the two-dimensional ferrovalley material VSi2N4

Abstract

Due to their novel spin and valley properties, two-dimensional (2D) ferrovalley materials are expected to be promising candidates for next-generation spintronic and valleytronic devices. However, they are subject to various defects in practical applications. Therefore, the electronic, valley, and magnetic properties may be modified in the presence of the defects. In this work, utilizing first-principles calculations, we systematically studied the effects of defects on the electronic, valley, and magnetic properties of the 2D ferrovalley material VSi2N4. It has been found that C doping, O doping, and N vacancies result in the half-metallic feature, Si vacancies result in the metallic feature, and V vacancies result in a bipolar gapless semiconductor. These defect-induced electronic properties can be effectively tuned by changing defect concentration and layer thickness. Since the impurity bands do not affect the K and K′ valleys, valley polarization is well maintained in O-doped and N-defective systems. Importantly, these defects play a crucial role in modifying the magnetic properties of the pristine VSi2N4, especially the magnitude of local magnetic moments and the magnetic anisotropy energy. Detailed analysis of the density of states demonstrates that the variations of the total magnetic moment and magnetic anisotropy energy with biaxial strain are determined by the electronic states near the Fermi level rather than the type of defect, which provides a new understanding of the effects of defects on the magnetic properties of 2D materials. Moreover, the layer thickness can affect the magnetic coupling between defects and surrounding V atoms. Our results offer insight into the electronic, valley, and magnetic properties of VSi2N4 in the presence of various point defects.

Graphical abstract: Defect effects on the electronic, valley, and magnetic properties of the two-dimensional ferrovalley material VSi2N4

Supplementary files

Article information

Article type
Paper
Submitted
23 Mar 2024
Accepted
27 May 2024
First published
28 May 2024

Dalton Trans., 2024,53, 10603-10617

Defect effects on the electronic, valley, and magnetic properties of the two-dimensional ferrovalley material VSi2N4

M. Liu, G. Li, Y. He and K. Xiong, Dalton Trans., 2024, 53, 10603 DOI: 10.1039/D4DT00856A

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