Ultrahigh-resolution spin-echo measurement of surface potential energy landscapes.
We demonstrate two approaches that use the recently developed helium spin-echo technique to measure surface potential energy landscapes. For helium-lithium fluoride (100), we use the selective adsorption phenomenon to obtain the complete experimental band structure of atoms in a corrugated surface potential. For carbon monoxide-copper (001), we measure the diffusion-induced energy broadening in the scattered helium beam and extract properties of the adsorbate-substrate potential. The measurements are made possible by the resolution of our new spectrometer, which improves on existing resolution by three orders of magnitude. We show that it is possible to produce benchmark energy landscapes to assist evaluation and development of first-principles theory in the problematic van der Waals/weak chemisorption regime.
Jardine
Andrew P
AP
Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE, UK. apj24@cam.ac.uk
Dworski
Shechar
S
Fouquet
Peter
P
Alexandrowicz
Gil
G
Riley
David J
DJ
Lee
Gabriel Y H
GY
Ellis
John
J
Allison
William
W