STM study of the Mn-dopants on the surface of Sr$_{3}$(Ru$_{1-x}$Mn$_{x})_{2}$O$_{7}$(x=6{\%}, 16{\%})

ORAL

Abstract

The double-layered Sr$_{3}$Ru$_{2}$O$_{7 }$is a paramagnetic metal, but the substitution of Mn for Ru (Sr$_{3}$(Ru$_{1-x}$Mn$_{x})_{2}$O$_{7})$ results in a metal-to-insulator transition at T$_{MIT}$ and antiferromagnetic (AF) ordering at T$_{M}$ (the two transitions are closely coupled for x $<$ 6{\%}). STM measurements at 4.2 K and 100 K on the surface of Sr$_{3}$(Ru$_{1-x}$Mn$_{x})_{2}$O$_{7}$ ($x$ = 6{\%}, 16{\%}) reveal a ($\surd $2 $\times \surd $2)R45$^{o}$ unit cell, consistent with the orthorhombic bulk structure. The Mn dopant has been identified through bias-dependent STM topography and dI/dV mapping. The Mn dopant equally occupies two sites which are anti-phase - one sitting at the center and the other on the corner of the ($\surd $2 $\times \surd $2)R45$^{\circ}$ unit cell. We have directly imaged the chirality of MnO$_{6}$ rotation at the anti-phase sites. In contrast to the bulk measurements, the surface is always metallic for $x $= 16{\%} and insulating only for 4.2K measurements on the $x$ = 6{\%} sample. The surface apparently suppresses the Mn-induced insulating (AF) phase observed in the bulk.

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Authors

  • E.W. Plummer

    Louisiana State University, Louisiana State University, Baton Rouge, LA 70803, USA, Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803, Dept. of Physics, Louisiana State University, Baton Rouge, LA 70802

  • Guorong Li

    Louisiana State University, Louisiana State University, Baton Rouge, LA 70803, USA

  • Qing Li

    Oak Ridge National Laboratory, Center for Nanophase Materials Sciences Division, Oak Ridge National Laboratory, USA, Center of Nanophase Materials Sciences, Oak Ridge National Laboratory, TN, USA 37831

  • Minghu Pan

    Oak Ridge National Laboratory, Center for Nanophase Materials Sciences Division, Oak Ridge National Laboratory, USA, Center of Nanophase Materials Sciences, Oak Ridge National Laboratory, TN, USA 37831

  • Biao Hu

    Louisiana State University, Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803, Dept. of Physics, Louisiana State University, Baton Rouge, LA 70802

  • Von Braun Nascimento

    Louisiana State University, Louisiana State University, Baton Rouge, LA 70803, USA

  • Jiandi Zhang

    Louisiana State University, Louisiana State University, Baton Rouge, LA 70803, USA, Dept. of Physics, Louisiana State University, Baton Rouge, LA 70802

  • Rongying Jin

    Louisiana State University, Louisiana State University, Baton Rouge, LA 70803, USA, Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803, Dept. of Physics, Louisiana State University, Baton Rouge, LA 70802