Lin C L, Lu S M, Su W B, Shih H T, Wu B F, Yao Y D, Chang C S, Tsong Tien T
Institute of Physics, Academia Sinica, Nankang, Taipei, Taiwan, Republic of China.
Phys Rev Lett. 2007 Nov 23;99(21):216103. doi: 10.1103/PhysRevLett.99.216103. Epub 2007 Nov 20.
Gundlach oscillation (or the standing-wave state) is a general phenomenon manifesting in the tunneling spectrum acquired from a metal surface using scanning tunneling spectroscopy. Previous studies relate the energy shift between peaks of the lowest-order Gundlach oscillation observed on the thin film and the metal substrate to the difference in their work functions. By observing Gundlach oscillations on Ag/Au(111), Ag/Cu(111), and Co/Cu(111) systems, we demonstrate that the work function difference is not the energy shift of the lowest order but the ones of higher order where a constant energy shift exhibits. Higher order Gundlach oscillations can thus be applied to determine the work function of thin metal films precisely.
贡德拉克振荡（或驻波状态）是一种普遍现象，出现在使用扫描隧道光谱从金属表面获取的隧道光谱中。先前的研究将在薄膜和金属衬底上观察到的最低阶贡德拉克振荡峰之间的能量 shift 与它们的功函数差异联系起来。通过观察 Ag/Au(111)、Ag/Cu(111) 和 Co/Cu(111) 系统上的贡德拉克振荡，我们证明功函数差异不是最低阶的能量 shift，而是具有恒定能量 shift 的高阶能量 shift。因此，高阶贡德拉克振荡可用于精确确定薄金属膜的功函数。
