Manifestation of work function difference in high order Gundlach oscillation.
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.
Lin
C L
CL
Institute of Physics, Academia Sinica, Nankang, Taipei, Taiwan, Republic of China.
Lu
S M
SM
Su
W B
WB
Shih
H T
HT
Wu
B F
BF
Yao
Y D
YD
Chang
C S
CS
Tsong
Tien T
TT