Centers & Labs

RIKEN Center for Emergent Matter Science

Strong Correlation Theory Research Group

Group Director: Naoto Nagaosa (D.Sci.)
Naoto  Nagaosa(D.Sci.)

We study theoretically the strongly correlated electronic states in solids from the viewpoint of topology and explore new functions, including non-dissipative currents. Combining first-principles electronic structure calculations, analytic methods of quantum field theory and numerical analysis of models for correlated systems, we predict and design magnetic, optical, transport and thermal properties of correlated electrons focusing on their internal degrees of freedom such as spin and orbital. In particular, we study extensively the nontrivial interplay between these various properties, i.e., cross-correlation, and develop new concepts such as electron fractionalization and non-dissipative quantum operation by considering the topology given by the relativistic spin-orbit interaction and/or spin textures.

Main Research Field

Physics

Related Research Fields

Engineering

Research Subjects

  • Theory of spin textures in magnets: In chiral magnets, it is possible that the spins show nontrivial configuration, i.e., spin textures. We study theoretically the dynamics of the skyrmion, which is a representative topological particle in magnets, by the numerical simulation and field theoretical methods.
  • Theory of topological insulators: Topological insulator is a new state of matter, and their physical properties are mostly unexplored yet. We study the transport, optical, and magnetic properties of topological insulators and search for the new possibilities such as the gigantic magneto-electric coupling and new types of excitations. Also the theoretical design of transport phenomena in the interface and junction systems is in progress in terms of the first-principles band structure calculations.
  • Theory of real-time quantum processes: We study the time-dependent quantum dynamics including the electric field induced Mott breakdown and time-dependent control of spin-orbit interaction. By using the time-dependent quantum simulations, we are aiming to explore the quantum functions utilizing the time-axis.

Selected Publications

Papers with an asterisk(*) are based on research conducted outside of RIKEN.
  1. A. S. Mishchenko, N. Nagaosa, N. Prokof’ev.:
    "Diagrammatic Monte Carlo Method for Many-Polaron Problems"
    Phys. Rev. Lett. 113, 166402. (2014).
  2. M. Mochizuki, XZ. Yu, S. Seki, N. Kanazawa, W, Koshibae, J. Zang, M. Mostovoy, Y. Tokura, N. Nagaosa.:
    "Thermally driven ratchet motion of a skyrmion microcrystal and topological magnon Hall effect"
    Nature Materials 13, 241. (2014).
  3. J. Iwasaki, M. Mochizuki, N. Nagaosa.:
    "Universal current-velocity relation of skyrmion motion in chiral magnets"
    Nature Communications 4, 1463. (2013).
  4. N. Nagaosa, J. Sinova, S. Onoda, A. H. MacDonald, N. P. Ong.:
    "Anomalous Hall effect"
    Rev. Mod. Phys. 82, 1539. (2010).
  5. Y. Onose, et al.:
    "Observation of the Magnon Hall Effect"
    Science 329, 297. (2010).
  6. * P. A. Lee, N. Nagaosa, X. G. Wen.:
    "Doping a Mott insulator: Physics of high-temperature superconductivity"
    Rev. Mod. Phys. 78, 17. (2006).
  7. * S. Murakami, N. Nagaosa, S. C. Zhang.:
    "Dissipationless quantum spin current at room temperature"
    Science 301, 1348. (2003).
  8. * Z. Fang, et al.:
    "The anomalous Hall effect and magnetic monopoles in momentum space"
    Science 302, 92. (2003).
  9. * Y. Tokura, N. Nagaosa.:
    "Orbital Physics in Transition-Metal Oxides"
    Science 288, 462. (2000).
  10. * S. Ishihara, M. Yamanaka, N. Nagaosa.:
    "Orbital Liquid in La1-xSrxMnO3"
    Phys. Rev. B 56, 686. (1997).

Lab Members

Principal Investigator

Naoto Nagaosa
Group Director

Core Members

Wataru Koshibae
Senior Scientist
Andrey Mishchenko
Senior Scientist
Makoto Yamaguchi
Postdoctoral Researcher
Shintaro Hoshino
Postdoctoral Researcher
Yusuke Hama
Special Postdoctoral Researcher

Contact information

Frontier Research Laboratory, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan

Email: nagaosa [at] riken.jp

Related links

Recent research results

March 3, 2017: RIKEN RESEARCH
Weyl fermions, on the other hand
July 29, 2016: RIKEN RESEARCH
A new tilt on an old particle
September 4, 2015: RIKEN RESEARCH
Spins on the edge
August 28, 2015: RIKEN RESEARCH
Electrons take a phonon bath