Energy dissipation in dynamic force microscopy on KBr(001) correlated with atomic-scale adhesion phenomena
Energy dissipation in dynamic force microscopy on KBr(001) correlated with atomic-scale adhesion phenomena
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DOI：
10.1103/physrevb.86.245419
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发表时间：
2012-12-17
影响因子：
3.7
通讯作者：
Meyer, Ernst
中科院分区：
文献类型：
--
作者：
Kawai, Shigeki;Glatzel, Thilo;Meyer, Ernst
采用动态力谱技术研究了室温下KBr针尖与样品之间的原子尺度粘附现象，其振幅最小可达285 pm。硅悬臂的第二弯曲模式的高谐振频率（近似1 MHz）抑制了由悬臂和抖动压电致动器之间的不期望的机械耦合引起的表观耗散能量。此外，焦耳热耗散贡献和噪声等效耗散能量通过设置较小的振幅被减小。使用一个高的共振频率和较小的振幅，使我们能够进行高灵敏度的测量原子尺度的粘附和尖端不稳定性相关的能量耗散。尖端的变化，所造成的尖端样品相互作用和热能，导致在三个不同的耗散能量水平（Δ E-ts约为25毫电子伏/周期）。尖端顶点条件的这种不频繁的变化经常妨碍具有小幅度的稳定成像。系统的测量结果表明，原子的粘附主要是由针尖本身引起的，针尖越尖越软，原子的能量耗散越大。DOI：10.1103/PhysRevB.86.245419
Atomic-scale adhesion phenomena between KBr tip and sample were studied by dynamic force spectroscopy with a small amplitude of down to 285 pm at room temperature. The high-resonance frequency of the second flexural mode of a silicon cantilever (approximate to 1 MHz) suppresses an apparent dissipation energy caused by undesirable mechanical couplings in between the cantilever and the dither piezo actuator. Further, the Joule heating dissipation contribution and the noise-equivalent dissipation energy were reduced by setting a smaller amplitude. Usage of a high resonance frequency and a smaller amplitude enables us to perform highly sensitive measurements of the atomic-scale adhesion and the tip-instability-related energy dissipation. Tip changes, caused by tip-sample interactions and thermal energy, resulted in three different dissipation energy levels (Delta E-ts approximate to 25 meV/cycle). This infrequent change of the tip apex condition often prevents a stable imaging with small amplitude. Our systematic measurement shows that the atomic adhesion is caused mainly in the tip itself, and a sharper and softer tip induced a larger energy dissipation. DOI: 10.1103/PhysRevB.86.245419