Abstract
Integrating methods in low-energy electron diffraction (LEED)—turning the instrument to low resolution in k∥—can reliably be used to study critical properties of continuous two-dimensional phase transitions and to determine critical exponents α and η. We performed systematic tests of the conditions under which an energy-like power dependence of the diffracted intensity of superstructure beams can be observed in order-disorder phase transitions of adsorbed atomic layers belonging to 3- and 4-state Potts universality classes. We further show that in the limit kξ ≫ 1 the exponent η can be determined reliably both below and above Tc using integrated intensities.