Stefan Blügel

Forschungszentrum Jülich

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Papers

Citation

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i-10 index

Research Trends

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Document Type

Co-Authors

Gustav Bihlmayer

Forschungszentrum Jülich

243

Yuriy Mokrousov

Forschungszentrum Jülich

200

Frank Freimuth

Forschungszentrum Jülich

Nicolae Atodiresei

Forschungszentrum Jülich

Vasile Caciuc

Forschungszentrum Jülich

Christoph Friedrich

Forschungszentrum Jülich

Phivos Mavropoulos

National and Kapodistrian University of Athens

Daniel Wortmann

Forschungszentrum Jülich

Samir Lounis

Forschungszentrum Jülich

B. Hillebrands

University of Kaiserslautern

Cooperative Institutions

Forschungszentrum Jülich

427

Centre National de la Recherche Scientifique

226

RWTH Aachen University

201

Jülich Aachen Research Alliance

165

Commissariat à l'Énergie Atomique et aux Énergies Alternatives

102

Ernst Ruska Centre

The University of Tokyo

Stadtwerke Jülich (Germany)

Universität Hamburg

Lawrence Berkeley National Laboratory

Author Statistics

Papers

Citation

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Research Field

Ground States of Constrained Systems: Application to Cerium Impurities

Physical Review Letters (1984)

P. H. Dederichs Stefan Blügel R. Zeller H. Akai

We present an extension of the density-functional theory to the lowest states compatible with arbitrary constraints. A broad class of interesting excitation problems connected with charge and magnetization fluctuations can be treated by such a method. We demonstrate the usefulness in ab initio calculations for Ce impurities.

10.1103/physrevlett.53.2512

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Citations (593)

Tunnelmagnetowiderstand

Physik Online (2018)

B. Hillebrands Stefan Blügel

10.1515/physiko.6.197

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Citations (0)

Direct and inverse spin-orbit torques

Physical Review B (2015)

Frank Freimuth Stefan Blügel Yuriy Mokrousov

The connection between the spin-orbit torque (SOT) and inverse spin-orbit torque (ISOT) in systems without inversion symmetry is studied by combining phenomenological models, diffusion theory, and density functional theory. Using this, DFT calculations on Co/Pt(111) magnetic bilayers expose the mechanisms underlying SOT and ISOT and highlight their reciprocity on the microscopic level.

Reciprocity

Point reflection

Orbit (dynamics)

10.1103/physrevb.92.064415

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Citations (88)

Atomic-scale magnetism of cobalt-intercalated graphene

Physical Review B (2013)

Régis Decker Jens Brede Nicolae Atodiresei Vasile Caciuc Stefan Blügel

Using spin-polarized scanning tunneling microscopy and density functional theory, we have studied the structural and magnetic properties of cobalt-intercalated graphene on Ir(111). The cobalt forms monolayer islands being pseudomorphic with the Ir(111) beneath the graphene. The strong bonding between graphene and cobalt leads to a high corrugation within the Moir\'e pattern which arises due to the lattice mismatch between the graphene and the Co on Ir(111). The intercalation regions exhibit an out-of-plane easy axis with an extremely high switching field, which surpasses the significant values reported for uncovered cobalt islands on Ir(111). Within the Moir\'e unit cell of the intercalation regions, we observe a site-dependent variation of the local effective spin polarization. State-of-the-art first-principles calculations show that the origin of this variation is a site-dependent magnetization of the graphene: At top sites the graphene is coupled ferromagnetically to the cobalt underneath, while it is antiferromagnetically coupled at fcc and hcp sites.

Magnetism

Atomic units

10.1103/physrevb.87.041403

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Citations (148)

Hund'sche Regeln

Physik Online (2018)

B. Hillebrands Stefan Blügel

10.1515/physiko.6.151

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Citations (0)

Tailoring the anomalous Hall effect of SrRuO3 thin films by strain: A first principles study

Journal of Applied Physics (2021)

Kartik Samanta Marjana Ležaić Stefan Blügel Yuriy Mokrousov

Motivated by the recently observed unconventional Hall effect in ultrathin films of ferromagnetic SrRuO3 (SRO), we investigate the effect of strain-induced oxygen octahedral distortion in the electronic structure and anomalous Hall response of the SRO ultrathin films by virtue of density functional theory calculations. Our findings reveal that the ferromagnetic SRO films grown on SrTiO3 (in-plane strain of −0.47%) have an orthorhombic (both tilting and rotation) distorted structure, and with an increasing amount of substrate induced compressive strain the octahedral tilting angle is found to be suppressed gradually, with SRO films grown on NdGaO3 (in-plane strain of −1.7%) stabilized in the tetragonal distorted structure (with zero tilting). Our Berry curvature calculations predict a positive value of the anomalous Hall conductivity of +76 S/cm at −1.7% strain, whereas it is found to be negative (−156 S/cm) at −0.47% strain. We attribute the found behavior of the anomalous Hall effect to the nodal point dynamics in the electronic structure arising in response to tailoring the oxygen octahedral distortion driven by the substrate induced strain. We also calculate strain-mediated anomalous Hall conductivity as a function of reduced magnetization obtained by scaling down the magnitude of the exchange field inside Ru atoms finding good qualitative agreement with experimental observations, which indicates a strong impact of longitudinal thermal fluctuations of Ru spin moments on the anomalous Hall effect in this system.

Tetragonal crystal system

Orthorhombic crystal system

10.1063/5.0043742

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Citations (7)

Manipulating magnetism through spin orbit interaction at interfaces

Stefan Blügel

Magnetism

Orbit (dynamics)

Source

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Citations (0)

Origin of incommensurate magnetic order in the RAlSi magnetic Weyl semimetals (R=Pr, Nd, Sm)

Physical review. B./Physical review. B (2024)

Juba Bouaziz Gustav Bihlmayer Christopher E. Patrick J. B. Staunton Stefan Blügel

We investigate rare-earth magnetic Weyl semimetals through first-principles simulations, analyzing the connection between incommensurate magnetic order and the presence of Weyl nodes in the electronic band structure. Focusing on PrAlSi, NdAlSi, and SmAlSi, we demonstrate that the reported helical ordering does not originate from the nesting of topological features at the Fermi surface or the Dzyaloshinskii-Moriya interaction. Instead, the helical order arises from frustrated isotropic short-range superexchange between the $4f$ moments facilitated by $pd$ hybridization with the main group elements. Employing a spin Hamiltonian with isotropic exchange and single-ion anisotropy we replicate the experimentally observed helical modulation.

Superexchange

Hamiltonian (control theory)

10.1103/physrevb.109.l201108

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Citations (5)

Interface-engineered templates for molecular spin memory devices

Nature (2013)

Karthik V. Raman A. M. Kamerbeek Arup Mukherjee Nicolae Atodiresei Tamal K. Sen

Spinplasmonics

Spin states

Magnetic storage

10.1038/nature11719

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Citations (427)

Spin-flip hot spots in ultrathin films of monovalent metals: Enhancement and anisotropy of the Elliott-Yafet parameter

Physical Review B (2013)

Nguyen H. Long Phivos Mavropoulos Swantje Heers Bernd Alois Zimmermann Yuriy Mokrousov

In contrast to the long-known fact that spin-flip hot spots, i.e., special $\mathbf{k}$ points on the Fermi surface showing a high spin-mixing parameter, do not occur in the bulk of monovalent (noble and alkali) metals, we found them on the surface Brillouin-zone boundary of ultrathin films of these metals. Density-functional calculations within the Korringa-Kohn-Rostoker Green function method for ultrathin (001) oriented Cu, Ag, and Au films of 10-layer thickness show that the region around the hot spots can have a substantial contribution, e.g., 52% in Au(001), to the integrated spin-mixing parameter, that could lead to a significant enhancement of the spin-relaxation rate or spin-Hall angle in thin films. Owing to the appearance of spin-flip hot spots, a large anisotropy of the Elliott-Yafet parameter [50% for Au(001)] is also found in these systems. The findings are important for spintronics applications in which noble metals are frequently used and in which the dimensionality of the sample is reduced.

Brillouin zone

10.1103/physrevb.88.144408

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Citations (11)