Theoretical studies on strongly correlated topological phases in transition metal oxides

2016 Fiscal Year Final Research Report

• Project/Area Number: 15K17702
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Condensed matter physics II
• Research Institution: The University of Tokyo
• Principal Investigator: YAMAJI Youhei 東京大学, 大学院工学系研究科(工学部), 准教授 (00649428)
• Project Period (FY): 2015-04-01 – 2017-03-31
• Keywords: 遷移金属酸化物 / スピン軌道相互作用 / 磁壁 / トポロジカル絶縁体 / 機能性界面

Outline of Final Research Achievements

Spontaneous symmetry breakings, metal-insulator transitions, and transport properties of magnetic-domain wall states in pyrochlore iridium oxides are studied by employing a symmetry-adapted effective Hamiltonian with a slab of the pyrochlore structure. Emergent metallic domain wall, which has an unconventional topological nature with a controllable and mobile metallic layer, is shown to host Fermi surfaces with modulated helical spin textures resembling Rashba metals. The helical nature of the domain-wall Fermi surfaces is experimentally detectable by anomalous Hall conductivity, circular dichroism, and optical Hall conductivity under external magnetic fields. Possible applications of the domain-wall metals to spin-current generation and “half-metallic” conduction are also discussed. The controllability of the domain walls is also clarified.
In addition to the iridium oxides, pair-annihilation of Weyl electrons and the emergence are studied in other pyrochlore transition metal oxides.

Free Research Field

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