# Thickness-dependent electronic and magnetic properties of $\gamma'$-Fe$_{\mathrm 4}$N atomic layers on Cu(001)

## TL;DR

This study investigates how the electronic and magnetic properties of $ ext{Fe}_4 ext{N}$ atomic layers on Cu(001) vary with thickness, revealing layer-dependent electronic states and magnetic moments through experimental and first-principles methods.

## Contribution

It provides new insights into the thickness-dependent electronic and magnetic properties of $ ext{Fe}_4 ext{N}$ layers on Cu(001), combining experimental observations with first-principles calculations.

## Key findings

- Thicker $ ext{Fe}_4 ext{N}$ layers show increased magnetic moments.
- Layer-resolved density of states explains electronic structure changes.
- Continuous trilayer films are successfully grown and characterized.

## Abstract

Growth, electronic and magnetic properties of $\gamma'$-Fe$_{4}$N atomic layers on Cu(001) are studied by scanning tunneling microscopy/spectroscopy and x-ray absorption spectroscopy/magnetic circular dichroism. A continuous film of ordered trilayer $\gamma'$-Fe$_{4}$N is obtained by Fe deposition under N$_{2}$ atmosphere onto monolayer Fe$_{2}$N/Cu(001), while the repetition of a bombardment with 0.5 keV N$^{+}$ ions during growth cycles results in imperfect bilayer $\gamma'$-Fe$_{4}$N. The increase in the sample thickness causes the change of the surface electronic structure, as well as the enhancement in the spin magnetic moment of Fe atoms reaching $\sim$ 1.4 $\mu_{\mathrm B}$/atom in the trilayer sample. The observed thickness-dependent properties of the system are well interpreted by layer-resolved density of states calculated using first principles, which demonstrates the strongly layer-dependent electronic states within each surface, subsurface, and interfacial plane of the $\gamma'$-Fe$_{4}$N atomic layers on Cu(001).