Visualization of Fermi’s Golden Rule Through Imaging of Light Emission from Atomic Silver Chains
Chi Chen,1
C. A. Bobisch,2
W. Ho1,2,*
Atomic-scale spatial imaging of one-dimensional chains of silver
atoms allows Fermi’s golden rule, a fundamental principle
governing optical transitions, to be visualized. We used a scanning
tunneling microscope (STM) to assemble a silver atom chain on
a nickel-aluminum alloy surface. Photon emission was induced
with electrons from the tip of the STM. The emission was spatially
resolved with subnanometer resolution by changing the tip position
along the chain. The number and positions of the emission maxima
in the photon images match those of the nodes in the differential
conductance images of particle-in-a-box states. This surprising
correlation between the emission maxima and nodes in the density
of states is a manifestation of Fermi’s golden rule in
real space for radiative transitions and provides an understanding
of the mechanism of STM-induced light emission.
2 Department of Physics and Astronomy, University of California, Irvine, CA 92697, USA.
* To whom correspondence should be addressed. E-mail: wilsonho{at}uci.edu
