Effect of electron- and hole-doping on properties of kagome-lattice ferromagnet Fe3Sn2

TL;DR

This theoretical study explores how Mn and Co substitution in Fe3Sn2 affects its electronic structure, magnetic properties, and band degeneracies, revealing doping-dependent modifications in its electronic and magnetic behavior.

Contribution

It provides new insights into how electron and hole doping via transition metal substitution influence the electronic and magnetic properties of kagome-lattice ferromagnet Fe3Sn2.

Findings

Hole doping decreases magnetic moments per Fe atom.

Electron doping with Co removes nodal band degeneracies.

Mn doping can suppress and then reintroduce nodal band degeneracies.

Abstract

We report a theoretical investigation of effects of Mn and Co substitution in the transition metal sites of the kagome-lattice ferromagnet, Fe3Sn2. Herein, hole- and electron-doping effects of Fe3Sn2 have been studied by density-functional theory calculations on the parent phase and on the substituted structural models of Fe3-xMxSn2 (M = Mn, Co; x = 0.5, 1.0). All optimized structures favor the ferromagnetic ground state. Analysis of the electronic density of states (DOS) and band structure plots reveals that the hole (electron) doping leads to a progressive decrease (increase) in the magnetic moment per Fe atom and per unit cell overall. The high DOS is retained nearby the Fermi level in the case of both Mn and Co substitutions. The electron doping with Co results in the loss of nodal band degeneracies, while in the case of hole doping with Mn emergent nodal band degeneracies and flatbands initially are suppressed in Fe2.5Mn0.5Sn2 but re-emerge in Fe2MnSn2. These results provide key insights into potential modifications of intriguing coupling between electronic and spin degrees of freedom observed in Fe3Sn2.