Self-organization at finite temperatures of the devil’s staircase in Pb/Si(111)

Abstract

The ``devil's staircase'' (DS) is one of the outstanding phase diagrams in physics because it shows a high degree of self-organization driven by a repulsive long-range adatom interaction. An infinite number of phases are predicted to exist which are built hierarchically with simple combinatorial rules. It was found with diffraction and scanning tunneling microscopy that a DS exists in Pb/Si (111) in the range $1.2l\ensuremath{\theta}l1.33$ monolayers, surprisingly at $\ensuremath{\sim}120\mathrm{K},$ and with phases which extend spatially over macroscopic distances $(\ensuremath{\sim}0.5\mathrm{mm}).$ The extraordinary amount of atom rearrangement necessary for these phases to form indicates an unexpected degree of self-organization at low temperatures.