Department of Physics, McGill University, Montreal, Quebec, Canada H3A 2T8.
Phys Rev Lett. 2010 Jan 8;104(1):017203. doi: 10.1103/PhysRevLett.104.017203.
We present theoretical and experimental results on the mechanical damping of an atomic force microscope cantilever strongly coupled to a self-assembled InAs quantum dot. When the cantilever oscillation amplitude is large, its motion dominates the charge dynamics of the dot which in turn leads to nonlinear, amplitude-dependent damping of the cantilever. We observe highly asymmetric line shapes of Coulomb blockade peaks in the damping that reflect the degeneracy of energy levels on the dot. Furthermore, we predict that excited state spectroscopy is possible by studying the damping versus oscillation amplitude, in analogy with varying the amplitude of an ac gate voltage.
我们提出了一种理论和实验结果，研究了与自组装 InAs 量子点强耦合的原子力显微镜悬臂的机械阻尼。当悬臂的振动幅度较大时，其运动主导了点的电荷动力学，从而导致悬臂的非线性、幅度相关阻尼。我们观察到在阻尼中库仑阻塞峰的高度非对称线形状，这反映了点上能级的简并性。此外，我们预测通过研究阻尼与振动幅度的关系，可以进行激发态光谱学研究，类似于改变交流栅极电压的幅度。
