Research Interest

The purpose of my research is studying spin-orbit coupling effects in magnetic multilayers. The advantage of spin-orbit coupling is that direct coupling between the spin angular momentum and the orbital motion allows for angular momentum flow from the lattice to electron spins. This allows manipulating and detecting magnetic states by applying an electrical current with high efficiency. Spin-orbit torque, which is a torque on magnetization induced by spin-orbit coupling, is a good example. Furthermore, other spin-related phenomena, such as spin motive force, magnetic damping, and magnetoresistance, are also significantly affected by spin-orbit coupling.

In magnetic multilayers, inversion symmetry is naturally broken, allowing new physics which have been protected by symmetry. The effects of symmetry breaking becomes more important when the dimension of the system goes down to nanoscale. Since the effective spin-orbit coupling parameter is magnified in the presence of symmetry breaking, the strong spin-orbit coupling effects not only give rise to quantitative corrections to known phenomena, but also result in qualitatively different behaviors.

Not only does spin-orbit copuling affect the magnetization dynamics in nonequilibrium situations, it also affects the equilibrium properties. Examples include the emergence of Dzyaloshinskii-Moriya interaction, perpendicular magnetic anisotropy, and skyrmion states. It means that the equilibrium properties are highly correlated with the nonequilibrium properties via the spin-orbit coupling parameter. Revealing such correlations would be not only deepen our understanding of spin-orbit coupling in magnetic nanostructures, but also advance the realization of spintronic device applications.

Expertise

• Magnetization dynamics
  • Spin-transfer torque and spin motive force
  • Magnetic damping and anisotropy
  • Motion of magnetic solitons
• Spin-orbit interaction in nanostructures
  • Spin-orbit coupling effects in magnetic bilayers
  • Interfacial spin-orbit coupling due to broken inversion symmetry
  • Spin-orbit torque

Publications (Highlights)

• "Field-free switching of perpendicular magnetization through spin-orbit torque in antiferromagnet/ferromagnet/oxide structures", Y.-W. Oh, S.-h. C. Baek, Y. M. Kim, H. Y. Lee, K.-D. Lee, C.-G. Yang, E.-S. Park, Ki-S. Lee, K.-W. Kim, G. Go, J.-R. Jeong, B.-C. Min, H.-W. Lee, K.-J. Lee, and B.-G. Park, Nature Nanotechnology 11, 878-884 (2016).
• "Chirality from interfacial spin-orbit coupling effects in magnetic bilayers", K.-W. Kim, H.-W. Lee, K.-J. Lee, and M. D. Stiles, Physical Review Letters 111, 216601 (2013).
• "Current-induced motion of a transverse magnetic domain wall in the presence of spin Hall effect", S.-M. Seo (equal), K.-W. Kim (equal), J. Ryu, H.-W. Lee, and K.-J. Lee, Applied Physics Letters 101, 022405 (2012).
• "Prediction of giant spin motive force due to Rashba spin-orbit coupling", K.-W. Kim, J.-H. Moon, K.-J. Lee, and H.-W. Lee, Physical Review Letters 108, 217202 (2012).
• "Magnetization dynamics induced by in-plane currents in ultrathin magnetic nanostructures with Rashba spin-orbit coupling", K.-W. Kim, S.-M. Seo, J. Ryu, K.-J. Lee, and H.-W. Lee, Physical Review B 85, 180404(R) (2012).

List with pictures

Expertise

• Solid state physics and materials science
• Atomistic simulations, density functional theory (DFT)
• Spin dynamics
• Monte Carlo simulations of frustrated magnets

Publications (Highlights)

• B. Dupé, G. Bilhmayer, M. Böttcher, S. Blügel, and S. Heinze "Engineering skyrmions in transition-metal multilayers for spintronics" Nature Communications, 2016, 7, 11779.
• B. Dupé, M. Hoffmann, C. Paillard, and S. Heinze "Tailoring magnetic skyrmions in ultra-thin transitions metal films" Nature Communications, 2014, 5, 4030.
• B. Dupé, I. C. Infante, G. Geneste, P.-E. Janolin, M. Bibes, A. Barthélémy, S. Lisenkov, L. Bellaiche, S. Ravy, B. Dkhil "Competing phases in BiFeO₃ thin films under compressive epitaxial strain" Physical Review B, 2010, 81, 144128.
• I. C. Infante, S. Lisenkov, B. Dupé, M. Bibes, S. Fusil, E. Jacquet, G. Geneste, S. Petit, A. Courtial, J. Juraszek, L. Bellaiche, A. Barthélémy, and B. Dkhil "Bridging multiferroic phase transitions by epitaxial strain in BiFeO₃" Physical Review Letters, 2010, 105, 057601.
• H. Béa, B. Dupé, S. Fusil, R. Mattana, E. Jacquet, B. Warot-Fonrose, F. Wilhelm, A. Rogalev, S. Petit, V. Cros, A. Anane, F. Petroff, K. Bouzehouane, G. Geneste, B. Dkhil, S. Lisenkov, I. Ponomareva, L. Bellaiche, M. Bibes, A. Barthélémy "Evidence for room-temperature multiferroicity in a compound with a giant axial ratio" Physical Review Letters, 2009, 21, 217603.

Research Interests

Atomistic simulations of multiferroics

Expertise

• Chemistry and materials science
• Atomistic simulations, density functional theory (DFT) and Monte-Carlo
• Functional materials (lead-free piezoelectrics, cathode materials for lithium ion batteries, phosphors)
• Structure-property relationships in perovskites
• Thermodynamic stability and point defects in dielectrics

Publications (Highlights)

• P. B. Groszewicz, M. Gröting, H. Breitzke, W. Jo, K. Albe, G. Buntkowsky, J. Rödel, Reconciling Local Structure Disorder and the Relaxor State in (Bi_1/2Na_1/2)TiO₃- BaTiO₃, Scientific Reports, 2016, 6, 31739.
• R. Hausbrand, G. Cherkashinin, H. Ehrenberg, M. Gröting, K. Albe, C. Hess, W. Jaegermann, Fundamental degradation mechanisms of layered oxide Li-ion battery cathode materials: Methodology, insights and novel approaches, Materials Science and Engineering: B, 2015, 192, 3-25.
• S. Li, J. Morasch, A.Klein, C. Chirila, L. Pintilie, L. Jia, K. Ellmer, M. Naderer, K. Reichmann, M. Gröting, K. Albe, Influence of orbital contributions to the valence band alignment of Bi₂O₃, Fe₂O₃, BiFeO₃, and Na_1/2Bi_1/2TiO₃, Physical Review B, 2013, 88, 045428.
• M. Gröting, I. Kornev, B. Dkhil, K. Albe, Pressure-induced phase transitions and structure of chemically ordered nanoregions in the lead-free relaxor ferroelectric Na_1/2Bi_1/2TiO₃, Physical Review B, 2012, 86, 134118.
• M. Gröting, S. Hayn, K. Albe, Chemical order and local structure of the lead-free relaxor ferroelectric Na_1/2Bi_1/2TiO₃, Journal of Solid State Chemistry, 2011, 184, 2041-2046.

Welcome. 🙂

My work sits at the nexus of two major trends of contemporary materials- and nano-science:

The first is the exploitation of the lower cost, greater abundance, greater tailorability and versatility of components based on organic molecules over traditional solid state materials in microtechnology.

The second is the use of the laws of quantum mechanics and powerful computers to predict highly accurate, atomically resolved properties of nano-systems. Such computational modeling from first-principles theory is exponentially developing into an essential, extremely cost-efficient tool for academic and industrial nanotechnological research alike.

Previously, I have modeled solid surfaces functionalized with single-molecule electrooptical motors, and worked on chemically tuning the electronic motion in novel solar cells based on organic molecules and quantum-dots. My methodological experience covers electronic structure theory in various forms from the solid state to quantum chemical methods.

Currently, I lead the Organic Spintronics Team. We work on developing molecular materials and components for spintronics from atomistic theoretical models, using the full gamut of modern first-principles and multi-scale modeling methods.

Publications (Highlights)

• "Polaron spin dynamics in high-mobility polymeric semiconductors", Nature Physics (2019)
• "Long spin diffusion lengths in doped conjugated polymers due to enhanced exchange coupling", Nature Electronics 2, 98 (2019)
• "Tuning the effective spin-orbit coupling in molecular semiconductors.", Nature Communications, 8, 15200 (2017)
• "Structure and energetics of azobenzene on Ag(111): benchmarking semiempirical dispersion correction approaches.", Physical Review Letters, 104, 36102 (2010)
• "Azobenzene at coinage metal surfaces: Role of dispersive van der Waals interactions.", Physical Review B, 80, 205410–14 (2009)

Awards & Fellowships

• Postdoctoral Fellowship at FOM AMOLF (Amsterdam, NL) / Max-Planck Institute for Polymer Research (Mainz, DE) (Feb 2012 – Oct 2014)
• Full Scholarship at International Max-Planck Research School (Berlin, DE) (Jan 2006 – May 2008)
• Full Scholarship at Institute for Pure and Applied Mathematics, UCLA (Los Angeles, USA) (Sep 2005 – Nov 2005)