Mitglied der HelmholtzGemeinschaft Impact of the large substrate
Mitglied der Helmholtz-Gemeinschaft Impact of the large substrate polarization on the magnetic anisotropy energy of 3 d adatoms on Pt(111) Mohammed Bouhassoune, Manuel dos Santos Dias, David S. G. Bauer and Samir Lounis Peter Grünberg Institut and Institute for Advanced Simulation In collaboration with A. Khajetoorians, J. Wiebe, R. Wiesendanger, University of Hamburg
Magnetic anisotropy energy • Stability of the magnetization due to MAE • Low dimension: MAE can be gigantic MAE (me. V) • Co adatom / Pt(111): MAE ~9. 3 me. V XMCD measurements Gambardella et al. Science 300, 1131 (2003)) 21 September 2021 Folie 1
Adatoms on Pt(111) : Importance of stacking • Large EMAE: out of plane • Spin excitation energy ESE related to the EMAE Co Fe ESE 10. 25 me. V EMAE out of plane 6. 53 me. V out of plane Balashov et al. PRL 102, 257203 (2009)) • fcc vs hcp stacking: EMAE differs STM tip Fe Pt(111) 21 September 2021 Tip Fe fcc Fe hcp ESE 0. 75 me. V EMAE out of plane 0. 19 me. V In plane Khajetoorians et al. PRL 111, 157204 (2013)) Folie 2
MAE for adatoms from ab-initio • DFT based impurity code • Full potential KKR Green function method • Spin-orbit coupling • 20% relaxation Surface Vac Fe Pt Code @ http: //www. judft. de 21 September 2021 Vac adatom Impurity Pt Details: David Bauer, Ph. D thesis, RWTH Aachen (2013) Folie 3
MAE for Fe adatoms on Pt(111) • SP: single particle • : out of plane • : in plane hcp 21 September 2021 fcc Folie 4
MAE for Fe adatoms on Pt(111) • SP: single particle • : out of plane • : in plane hcp 21 September 2021 fcc Folie 5
MAE for Fe adatoms on Pt(111) • SP: single particle • : out of plane • : in plane • MAE hcp in plane • MAE fcc out of plane hcp 21 September 2021 fcc Folie 6
MAE for Fe adatoms on Pt(111) • SP: single particle • : out of plane • : in plane • MAE hcp in plane • MAE fcc out of plane hcp 21 September 2021 fcc Folie 7
MAE induced and local terms • Dyson equation Vac • Spin-orbit interaction Fe S S-1 S-2 • change of the integrated density of states Pt • change of single particle energy • Two-site interactions 21 September 2021 Folie 8 Solovyev e al. PRB 52, 13419(1995)
MAE induced and local terms • System = Fe + nearest neighbors + 1 Pt atom Fe Induced intrinsic Pt : EMAE of cluster nearest neighbors • Manipulation of spin-orbit interaction: switch off : on-site term Cluster: nearest neighbors 21 September 2021 Folie 9
MAE induced term • System = Cluster of nearest neighbors+1 Pt (S-1) Vac Fe S S-1 S-2 Pt 21 September 2021 Folie 10
MAE induced term • System = Cluster of nearest neighbors+1 Pt (S-2) Vac Fe S S-1 S-2 Pt 21 September 2021 Folie 11
MAE induced term • System = Cluster of nearest neighbors+1 Pt Vac Fe S S-1 S-2 j Pt 21 September 2021 Folie 12
MAE induced term • MAE induced term for two different angles Vac Fe S S-1 S-2 j Pt 21 September 2021 Folie 13
MAE for Co, Mn, and Cr on Pt(111) • MAE fcc and hcp out of plane • MAE fcc and hcp in plane 21 September 2021 Folie 14
Summary • MAE for adatoms / Pt(111): strongly depends on binding site • Differences: Fe, Mn >> Co, Cr • Reason: Strong induced polarization in vicinal Pt atoms • Oscillations and decay with distance • Accurate MAE: Polarization cloud is important Acknowledgments: Helmholtz Centers for funding 21 September 2021 Fun. Silab research group Folie 15
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