A Novel Two-Dimensional Phase Transition:
the Disordering of the Knight-Move Phase
Lyle Roelofs '75, Provost of Colgate University
Thursday, April 7, 2011, 10:30 a.m., Science Building 101
Some high temperature superconducting films are grown through the "knight-move" phase (more technically designated 
). The nature of the disordering transition of this phase has not been determined, and it is likely relevant to the preparation of and technological processes involving these systems. We study the disordering of the knight-move phase in the form of a lattice gas system via Monte Carlo simulation and demonstrate that this disordering transition must be first order (discontinuous) in that case. This determination is based on an analysis of variation of the free energy densities through the transition. This new technique, which also provides a more intuitive window on transition order, is inspired by the classical ideas of Landau analysis. Taking advantage of the idea of universality applied to two-dimensional phase transitions, this determination of transition character can be extended to a wide variety of systems displaying ordered phases of this character.
