Interface induced magnetic polar metals by design

ORAL

Abstract

Polar metals with ferroelectric-like (FEL) displacements offer the promise of designing ferroelectrics with tunable band gaps [1,2]. One efficient way to induce FEL displacements in a centrosymmetric phase is by interface-induced coupling [3]. Here, using first-principles density functional theory (DFT) and DFT+U (static d-d Coulomb interaction) we investigate (BaTiO$_3$)$_6$/(SrRuO$_3$)$_n$/(BaTiO$_3$)$_7$ heterostrcutures (6/n/7), with n=1, 2 and 3. DFT calculations predict that a FEL phase coupled with in-plane rotation of RuO$_6$ octahedral ($a^0a^0c^+$) can be induced in centrosymmetric SrRuO$_3$ unit when BaTiO$_3$ is in a ferroelectric phase. Moreover, a spin crossover from low spin (2$\mu_B$, Bulk SrRuO$_3$) to high spin (4$\mu_B$, 6/3/7) is found driven by the FEL distortion, which is a rare phenomenon in case of magnetic polar metals. Experimental investigation has confirmed the induced polar distortion and the spin crossover. Finally, we discuss the design principles for spin crossover magnetic polar metals. [1] W. Cochran, Phys. Rev. Lett., 3, 412 (1959), [2] S. Ghosh et. al. Phys. Rev. Lett. 119, 177603 (2017), [3] H. Guo, PANS, 114, E5062-E5069 (2017).

*S.G and S.T.P are supported by DOE DE-FG02-09ER46554. H.G and E. W. P are supported by DOE DE-SC0002136

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Presenters

  • Saurabh Ghosh

    • SRM Research Institute and Dept. of Physics and Nanotechnology, SRM University
    • Department of Physics and Astronomy, Vanderbilt University

Authors

  • Saurabh Ghosh

    • SRM Research Institute and Dept. of Physics and Nanotechnology, SRM University
    • Department of Physics and Astronomy, Vanderbilt University

  • Hangwen Guo

    • Louisiana State Univ - Baton Rouge
    • Department of Physics, Louisiana State University
    • Dept. of Physics and Astronomy , Louisiana State University, USA
    • Department of Physics & Astronomy, Louisiana State University
    • Louisiana State University
    • Department of Physics and Astronomy, Louisiana State University

  • E Plummer

    • Physics and Astronomy, Louisiana State Univ - Baton Rouge
    • Department of Physcis and Astronomy, Louisiana State University
    • Louisiana State Univ - Baton Rouge
    • Department of Physics, Louisiana State University
    • Dept. of Physics and Astronomy , Louisiana State University, USA
    • Department of Physics & Astronomy, Louisiana State University
    • Department of Physics and Astronomy, Louisiana State University

  • Sokrates Pantelides

    • Department of Physics and Astronomy, Vanderbilt University
    • Vanderbilt University
    • Physics and Astronomy, Vanderbilt University
    • Department of Physics and Astronomy and Department of Electrical Engineering and Computer Science, Vanderbilt University
    • Dept. of Physics and Astronomy , Vanderbilt University
    • Vanderbilt Univ
    • Physics, Vanderbilt Univ