Spectral Evidence for Local-Moment Ferromagnetism in van der Waals Metals Fe${}_3$GaTe${}_2$ and Fe${}_3$GeTe${}_2$

Abstract

Magnetism in two-dimensional (2D) materials has attracted considerable attention recently for both fundamental understanding of magnetism and their tunability towards device applications. The isostructural Fe${}_3$GeTe${}_2$ and Fe${}_3$GaTe${}_2$ are two members of the Fe-based van der Waals (vdW) ferromagnet family, but exhibit very different Curie temperatures (T${}_C$) of 210 K and 360 K, respectively. Here, by using angle-resolved photoemission spectroscopy and density functional theory, we systematically compare the electronic structures of the two compounds. Qualitative similarities in the Fermi surface can be found between the two compounds, with expanded hole pockets in Fe${}_3$GaTe${}_2$ suggesting additional hole carriers compared to Fe${}_3$GeTe${}_2$. Interestingly, we observe no band shift in Fe${}_3$GaTe${}_2$ across its T${}_C$ of 360 K, compared to a small shift in Fe${}_3$GeTe${}_2$ across its T${}_C$ of 210 K. The weak temperature-dependent evolution strongly deviates from the expectations of an itinerant Stoner mechanism. Our results suggest that itinerant electrons have minimal contributions to the enhancement of T${}_C$ in Fe${}_3$GaTe${}_2$ compared to Fe${}_3$GeTe${}_2$, and that the nature of ferromagnetism in these Fe-based vdW ferromagnets must be understood with considerations of the electron correlations.

References in corpus (20)

• Magnetic 2D materials and heterostructures
• Theory of quasiparticle spectra for Fe, Co, and Ni: bulk and surface
• Quasiparticle Mass Enhancement and Temperature Dependence of the Electronic Structure of Ferromagnetic SrRuO3 Thin Films
• Room-temperature and tunable tunneling magnetoresistance in Fe3GaTe2-based all-2D van der Waals heterojunctions with high spin polarization
• Room-Temperature Spin-Valve Effect in Fe${}_3$GaTe${}_2$/MoS${}_2$/Fe${}_3$GaTe${}_2$ 2D van der Waals Heterojunction Devices
• Pervasive beyond room-temperature ferromagnetism in a doped van der Waals magnet: Ni doped Fe${}_5$GeTe${}_2$ with $T_{\text{C}}$ up to 478 K
• Tremendous tunneling magnetoresistance effects based on van der Waals room-temperature ferromagnet Fe${}_3$GaTe${}_2$ with highly spin-polarized Fermi surfaces
• Non-Thermal Emergence of an Orbital-Selective Mott Phase in FeTe${}_{1-x}$Se${}_x$
• Correlation-Driven Electronic Reconstruction in FeTe${}_{1-x}$Se${}_x$
• Nonsymmorphic Symmetry-Protected Band Crossings in a Square-Net Metal PtPb${}_4$
• Neutron spectroscopy evidence on the dual nature of magnetic excitations in a van der Waals metallic ferromagnet Fe${}_{2.72}$GeTe${}_2$
• Anisotropic magnon damping by zero-temperature quantum fluctuations in ferromagnetic CrGeTe${}_3$
• Observation of spin-dependent dual ferromagnetism in perovskite ruthenates
• $\mathrm{F}{\mathrm{e}}_3\mathrm{GeT}{\mathrm{e}}_2$: A site-differentiated Hund metal
• Antiferromagnetic order in Co-doped Fe${}_5$GeTe${}_2$ probed by resonant magnetic x-ray scattering
• Thermal cycling induced alteration of the stacking order and spin-flip in the room temperature van der Waals magnet Fe${}_5$GeTe${}_2$
• Magnetic molecular orbitals in MnSi
• Flatband-Induced Itinerant Ferromagnetism in RbCo${}_2$Se${}_2$
• Two-Step Electronic Response to Magnetic Ordering in a van der Waals Ferromagnet
• Strongly correlated electrons in superconducting islands with fluctuating Cooper pairs

Cited by in corpus (7)

• Roadmap on Quantum Magnetic Materials
• Mechanism of magnetic phase transition in correlated magnetic metal: insight into itinerant ferromagnet Fe${}_{3-\delta }$GeTe${}_2$
• DFT+DMFT investigation of the magnetic phase transition in the itinerant ferromagnet Fe${}_3$GaTe${}_2$
• Above-room-temperature ferromagnetism in large-area epitaxial Fe3GaTe2/graphene van der Waals heterostructures
• Unusual ferromagnetic band evolution and high Curie temperature in monolayer 1T-CrTe2 on bilayer graphene
• Dichotomy of flat bands in the van der Waals ferromagnet Fe${}_5$GeTe${}_2$
• Why Fe${}_3$GaTe${}_2$ has higher Curie temperature than Fe${}_3$GeTe${}_2$?