Optical Study of Metal-Insulator Transition in the Ferromagnetic Ground State of La_<1-x>Sr_xMnO_3 : Condensed Matter: Electronic Properties, etc.

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概要

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• Optical spectra for the ferromagnetic ground states have been investigated for single crystals of perovskite-type manganese oxides La_<1-x>Sr_xMnO_3 with finely varying hole-doping concentration (x) around the metal-insulator (MI) phase boundary (x_c 〜 0.16). For such a fully spin-polarized state, orbital degree of freedom may play an important role in the MI transition, which is anticipated to be figured out in terms of optical spectroscopy. In the ferromagnetic ground state, the low-energy optical conductivity spectra are observed to vary from Drude-1ike (typically for x = 0.4) to incoherent broad feature (for x < 0.2) with decreasing x. The spectral-weight analysis shows that the kinetic energy of conduction electron scarcely changes with change of x when viewed on a large energy scale (about 1 eV) whereas the coherent response on a low energy scale (〜0.1 eV) is critically suppressed toward the insulating phase. Orbital correlation and its coupling with lattice dynamics are likely responsible for such an anomalous variation of charge dynamics. Far-infrared pseudo gap struc.ture observed in the ferromagnetic metallic phase of x = 0.16 on the verge of MI transition suggests the charge localization affected by randomness and non-local interaction in the course of orbital and charge ordering.

• 社団法人日本物理学会の論文
• 2000-11-15

著者

• Asamitsu Atsushi

  Cryogenic Center University Of Tokyo

• SAITOH Eiji

  Department of Applied Physics, University of Tokyo

• OKIMOTO Youichi

  Joint Research Center for Atom Technology (JRCAT)

• KOKUDA Yoshinori

  Department of Applied Physics, University of Tokyo

• Saitoh E

  Department Of Applied Physics University Of Tokyo

• Saitoh Eiji

  Department Of Applied Physics University Of Tokyo

• Kokuda Yoshinori

  Department Of Applied Physics University Of Tokyo:joint Research Center For Atom Technology (jrcat)

関連論文

• Effect of Quenched Disorder on Charge-Orbital-Spin Ordering in Single-Layer Manganites(Condensed Matter: Structure, Mechanical and Thermal Properties)
• Fermi Surface and Band Dispersions of M_xCoC_2 (M: Na, K, and Rb) Studied by Angle-Resolved Photoemission Spectroscopy(Condensed matter: electronic structure and electrical, magnetic, and optical properties)
• Directional Ordering and Collective Fluctuation of Orbital in a Colossal Magnetoresistive Manganite : Condensed Matter: Electronic Properties, etc.
• Optical Study of Metal-Insulator Transition in the Ferromagnetic Ground State of La_Sr_xMnO_3 : Condensed Matter: Electronic Properties, etc.
• Observations of Single Magnetic Domain Wall in Nanomagnet by Magnetic Force Microscopy

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