Robust Ferromagnetism in Hexagonal Honeycomb Transition Metal Nitride Monolayer

TL;DR

This paper introduces two new 2D magnetic materials, VN2 and FeN2, which show stable ferromagnetism at relatively high temperatures, making them promising for spintronic applications.

Contribution

The study proposes and validates new 2D transition metal nitrides with intrinsic ferromagnetism and high Curie temperatures.

Findings

VN2 and FeN2 monolayers are structurally stable as shown by formation energy, phonon spectra, and molecular dynamics.

Both materials exhibit ferromagnetic ground states with Curie temperatures of 222 K and 238 K, respectively.

VN2 and FeN2 show high-temperature ferromagnetism or large-gap half-metallicity.

Abstract

Two-dimensional intrinsic magnetic materials with high Curie temperature are promising candidates for next-generation spintronic devices. In this work, we design two kinds of two-dimensional transition metal nitrides, VN2 and FeN2, both with a hexagonal honeycomb lattice. Based on the formation energy, and phonon spectra calculations as well as the molecular dynamics simulations, their structural stability is demonstrated. Then, we determine the ferromagnetic ground states of VN2 and FeN2 monolayers through the energy calculations, and the Curie temperatures of 222 K and 238 K are estimated by solving the Heisenberg model using the Monte Carlo simulation method. Hence, the VN2 and FeN2 monolayers are demonstrated to be new two-dimensional ferromagnetic materials with high temperature ferromagnetism or large-gap half-metallicity.

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