Measurement of Si(111) surface stress by a microscopic technique

We have developed a method for the local measurement of surface stress using transmission electron microscopy. Applying this technique to the clean Si(111) surface during 7×7-1×1 phase coexistence, we determine the stress difference between the phases to be 30±5 meV/A${\mathrm{̊}}^2$. This relatively small difference is consistent with the presence of adatoms in the 1×1 surface. The method can be easily extended to other surfaces and interfaces that have well-defined domain boundaries.