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用扫描隧道显微镜 (STM)对Cu(111) Au和Cu(111) Pd表面的局域功函数进行了研究 .通过测量隧道电流对针尖样品间距的响应 ,得到了与STM形貌图一一对应的表面局域功函数图像 .实验发现 ,Au Pd覆盖层和Cu衬底间的功函数有明显的不同 .Pd薄膜的功函数甚至超过了其体本征值 ,且功函数在台阶处变小 .用偶极子的形成解释了台阶处功函数的降低 .这一工作表明 ,用测量局域功函数的方法容易区分表面上不同的元素 ,并具有纳米尺度的空间分辨率 .
The local work function of Cu (111) Au and Cu (111) Pd surface was investigated by scanning tunneling microscope (STM). By measuring the response of tunneling current to the tip-tip sample spacing, It is found that the work function between the Au Pd cladding layer and the Cu substrate is obviously different.The work function of the Pd film even exceeds its body eigenvalue and the work function becomes smaller at the step The dipole formation explains the reduction of the work function at the step, which shows that it is easy to distinguish superficially different elements with the method of measuring local work function, and has a spatial resolution of nanometers.