Observation of charge glass formation dynamics by femtosecond optical excitation and investigation of momentum space structure

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K03706
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 13030:Magnetism, superconductivity and strongly correlated systems-related
• Research Institution: Hokkaido University
• Principal Investigator: Tsuchiya Satoshi 北海道大学, 工学研究院, 助教 (80597633)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 長距離電荷秩序 / 短距離電荷秩序 / 空間非一様性

Outline of Final Research Achievements

Toward the final goal of this research, "elucidation of glass transition," we have focused on "charge glass" (the glass of electrons) in organic molecular crystals, which has attracted much attention in recent years, and investigated the properties of charge glass from the polarization and temperature characteristics of the photoinduced carrier relaxation dynamics by pump-probe spectroscopy using optical pulses. When temperature decreases, the polarization-dependent dynamics shows that the signal amplitude increases in the crystal of electrons (charge ordered state) but does not change in the charge glass. This behavior indicates that in the charge ordered state , the electrons are spatially uniformly aligned, whereas in the charge glass state, the electrons are partially aligned, but over very short distances and the direction of alignment is not uniform.

Free Research Field

物性物理学

Academic Significance and Societal Importance of the Research Achievements

本研究は光パルスによる時間分解分光測定によって、従来ガラス研究の対象となってきた分子とは異なり、構造のない素粒子である電子が空間的にどのような構造を持ってガラス化するかという問題に新たな知見を与えた。また本成果はこの時間分解測定が電子ガラスの性質を明らかにする上で有効であることを示すものであり、今後本測定の特性を活かし、時間領域でのガラス化過程を調査できれば、ガラス転移の時空間構造を明らかにすることができる。ガラス転移の解明は物理学、材料工学、情報工学、生物学などの幅広い分野に通じており、その波及効果は計り知れない。