2018/10/31 by M. Suzuki, B. Gao, K. Koshiishi +12 · 1 citation
Physics and Astronomy · #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.99.161401
published as Phys. Rev. B 99, 161401 (2019) · 11 pages, 3 figures
arxiv created 2019/01/25 · arxiv updated 2019/04/10
In order to investigate the electronic properties of the semiconducting van der Waals ferromagnet Cr2Ge2Te6 (CGT), where ferromagnetic layers are bonded through van der Waals forces, we have performed angle-resolved photoemission spectroscopy (ARPES) measurements and density-functional-theory (DFT+U) calculations. The valence-band maximum at the Γ point is located ∼ 0.2 eV below the Fermi level, consistent with the semiconducting property of CGT. Comparison of the experimental density of states with the DFT calculation has suggested that Coulomb interaction between the Cr 3d electrons U\rm eff ∼ 1.1 eV. The DFT+U calculation indicates that magnetic coupling between Cr atoms within the layer is ferromagnetic if Coulomb U \rm eff is smaller than 3.0 eV and that the inter-layer coupling is ferromagnetic below U\rm eff ∼ 1.0 eV. We therefore conclude that, for U\rm eff deduced by the experiment, the intra-layer Cr-Cr coupling is ferromagnetic and the inter-layer coupling is near the boundary between ferromagnetic and antiferromagnetic, which means experimentally deduced U\rm eff is consistent with theoretical ferromagnetic condition.