Development of STM/Thermal Vibration AFM for Simultaneous Measurement of Single Molecular Conductivity and Rigidity

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K15175
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 29020:Thin film/surface and interfacial physical properties-related
• Research Institution: Yokohama City University
• Principal Investigator: OOE Hiroaki 横浜市立大学, 理学部, 助教 (20793194)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 原子間力顕微鏡 / 熱振動 / 分子チェーン

Outline of Final Research Achievements

For simultaneous measurement of complex atomic/molecuar properties on solid surface (e.g. correlation of conductivity, stiffness, and elasticity of molecular wires on a metal surface), we tried to develop conpound scanning probe microscopy having functions of Scaning Tunneling Microscopy (STM) and thermalvibration Atomic Force Microscopy (AFM).
Conventionally, the thermalvibration amplitude of AFM cantilever, which is only a few picometers, has hard to use for the force measurement. However, we have adopted the integrated FFT signal of the AFM cantilever vibration to improve the signal-to-noise ratio. Consequently, we have demonstarted that the force detection by thermalvibration with a wide dynamic range from attractive to repulsive interactions.

Free Research Field

表面物理

Academic Significance and Societal Importance of the Research Achievements

本研究では、既存装置では難しい超微小振幅でのＡＦＭ計測の可能性を検討した。その結果、ＡＦＭカンチレバーの原理的最小振幅である熱振動を利用して、共振スペクトル（振動振幅密度の周波数依存性）の変形を通して引力から斥力まで広い範囲で力計測が可能であることが明らかになった。ＡＦＭカンチレバーの硬さが約１ｋＮ／ｍ、温度が３００Ｋのとき、熱振動振幅は約１ピコメートルである。これは原子分子の１％程度の微小サイズであるため、例えば分子チェーンの連絡部の屈曲による電気伝導特性の変化などのような静的な複合計測への応用が期待できる。