Magnetoelastic and Magnetoelectric Coupling in Two-Dimensional Nitride MXenes: A Density Functional Theory Study

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) multiferroic materials are crucial for next-generation electronics, offering potential for high-density, low-power data storage and spintronics.
• MXenes, a family of 2D transition metal carbides and nitrides discovered in 2011, have emerged as key research subjects across various scientific disciplines.

Purpose of the Study:

• To investigate the structural, electronic, and magnetic properties of specific nitride MXenes.
• To explore the potential of these materials in multiferroic applications.

Main Methods:

• First-principles calculations were employed to analyze lattice structures, electronic band gaps, and magnetic ordering.
• The study focused on nitride MXenes such as V₂NF₂, V₂NO₂, Cr₂NF₂, Mo₂NO₂, Mo₂NF₂, and Mn₂NO₂, as well as Janus variants.

Main Results:

• Several nitride MXenes exhibit intrinsic band gaps and orbital ordering, which can lead to magnetoelastic or magnetoelectric coupling.
• Cr₂NF₂ was identified as a ferroelastic material with coupled spiral magnetic order and strain.
• Ferroelectric phases were observed as excited states in V₂NO₂, Cr₂NF₂, and Mo₂NF₂, with coupled magnetic order and polar displacements.
• Magnetoelectric coupling effects were also found in Janus MXenes (V₈N₄O₇F, Cr₈N₄F₇O, Mo₈N₄F₇O).
• Mo₈N₄F₇O phases, characterized by orbital ordering, demonstrated switchability via external strain or electric fields.

Conclusions:

• Nitride MXenes possess promising characteristics for 2D multiferroic applications.
• The observed magnetoelectric coupling and switchable phases highlight their potential for advanced electronic devices.