Theory and feasibility of using low-energy electron diffraction to study specific-heat anomalies at surface phase transitions.

Abstract

We expound the idea that as a probe of short-range order, low-energy electron diffraction can be used to study the energy singularity associated with surface phase transitions. We demonstrate its feasibility by performing Monte Carlo simulations on two triangular lattice gases with second-order transitions in universality classes distinguished by the critical exponent \ensuremath{\alpha}: The first has a (\ensuremath{\surd}3 \ifmmode\times\else\texttimes\fi{} \ensuremath{\surd}3 )R30\ifmmode^\circ\else\textdegree\fi{} ordered state; the second has a p(2\ifmmode\times\else\texttimes\fi{}2) ordered state. As multiple scattering is short ranged, it is no hindrance to this technique.