Unexpected charge effects in Mott insulators: Magnetoelectric behavior of Cr-trimer complexes

ORAL

Abstract

In this work we present measurements of the dielectric response as a function of magnetic field of Cr-trimer systems, which combined with recent theoretical developments indicates a magnetoelectric behavior evidenced by a purely electronic mechanism. Magnetic field strengths of the order of the exchange interaction (J $\sim $ t$^{2}$/U) strongly perturb the spin texture, which is evident as steps and plateaus in the magnetization behavior. The corresponding shifts in dielectric properties reveal the role of the charge degrees of freedom. Electron Spin Resonance (ESR) results indicates which terms in the effective spin Hamiltonian are responsible for the magnetoelectric coupling. Furthermore, we observe novel dipole-active ESR give rise to the possibility of negative refractive indices under special conditions.

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Authors

  • Oscar Ayala Valenzuela

    National High Magnetic Field Laboratory, Los Alamos National Laboratory, NHMFL-Los Alamos

  • Ross McDonald

    Los Alamos National Lab, National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos National Laboratory, NHMFL-Los Alamos

  • Mary C. Gurak

    National High Magnetic Field Laboratory, Los Alamos National Laboratory

  • C.D. Batista

    National High Magnetic Field Laboratory, Los Alamos National Laboratory, Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, USA, Los Alamos National Laboratory

  • P. Sengupta

    National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA

  • B. Mallick

    Ruhr-University Anorganische Chemie, Bochum, Germany

  • B. Mallick

    Ruhr-University Anorganische Chemie, Bochum, Germany

  • Marcelo Jaime

    National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos National Laboratory, MPA-CMMS, Los Alamos National Laboratory, NHMFL, Los Alamos National Laboratory, Los Alamos, NM, USA

  • J.A. Mydosh

    Kamerlingh Onnes Laboratory, Leiden University, The Netherlands