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Measuring the stress-strain relationship of correlated electron materials

日程 : 2022年8月30日(火) 16:00 - 17:00 場所 : Zoom及び物性研究所大講義室(A632)(ハイブリッド開催) 講師 : Clifford W. Hicks氏 所属 : School of Physics and Astronomy, University of Birmingham, U.K.
Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
世話人 : 岡隆史 中島多朗
e-mail: danwakai@issp.u-tokyo.ac.jp

  It is common procedure to measure the stress-strain relationship of engineering materials, but much less so for correlated electron materials. Reasons that this is a challenging measurement for correlated electron materials include the difficult mechanical properties of many electronically interesting materials, the need for low temperatures, and the need for strains of order 1% to observe interesting electronic effects. In this talk, I will tell you about the stress-strain relationship of the correlated metal Sr2RuO4. Compression along the [100] lattice direction drives the largest Fermi surface through a Lifshitz transition, from an electron-like to an open geometry. We find that the Young’s modulus has a sharp dip at this transition, by about 10% of its zero-stress value. This large effect can be explained mostly by band structure effects alone. Beyond the Lifshitz transition, the Young’s modulus rises by more than expected. I will also show Hall effect data, that indicate a pronounced change in electron-electron scattering across the Lifshitz transition.

【講師紹介】1軸歪みは、結晶対称性を容易に低下させることが可能で、競合する秩序状態を選択的に露わに物性に発現させたり、ファン・ホーベ特異点近傍の電子構造を制御し劇的な物性変化を齎したりと、物性研究には欠かせない物理パラメータとして近年注目されている。Hicks氏は、ピエゾ素子を巧みに組み込み、様々な物性測定装置へ搭載可能とするコンパクトかつパワフルな1軸圧力印加デバイスを開発し、電子構造のリフシッツ転移で超伝導転移温度の上昇を初めとする物性制御を開拓したり、超伝導と競合する3次元的電荷密度波状態を発現させる等で多彩な強相関電子物性を見出すなど、この研究分野を世界的にリードしている。皆様、是非ご参加ください。

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(公開日: 2022年08月05日)