The effect of Fe vacancies and Cu adhesion on the magnetic properties of Fe3GeTe2

Abstract

Fe₃GeTe₂ is a promising two-dimensional magnetic material that exhibits a high Curie temperature with monolayer geometry. Using the first principles calculation method, the effects of both Fe vacancies and contact with Cu electrodes on the magnetic properties of Fe₃GeTe₂ are studied. Calculation results determined that Fe vacancies occur preferentially on the Fe^II site. As a result, the magnetic moment of Fe^I ions decreases significantly, while the magnetic moment of Fe^II increases due to the presence of the Fe^II vacancies. The Cu(111) layers that act as the electrodes have moderately strong bonds with Fe₃GeTe₂ but they are found not to distort the primary structure of the Fe₃GeTe₂ monolayers, thus producing a stable Cu(111)/Fe₃GeTe₂ interface. The magnetic moments of Fe^I atoms at the Fe₃GeTe₂ layer surface decrease substantially following the adhesion of Cu(111) layers. The effect for other Fe atoms, however, is relatively weak. These results are useful for experimental studies and can promote the applications of Fe₃GeTe₂ in spin electronics.