Abstract. Using numerical simulations we show that a variety of novel colloidal crystalline states and multi-step melting phenomena occur on square and triangular two-dimensional periodic substrates. At half-integer fillings different kinds of frustration effects can be realized. A two-step melting transition can occur in which individual colloidal molecules initially rotate, destroying the overall orientational order, followed by the onset of interwell colloidal hopping, in good agreement with recent experiments.

PACS numbers: 82.70.Dd, 73.50.−h

Print publication: Issue 22 (6 June 2003)
Received 17 October 2002, in final form 6 January 2003
Published 22 May 2003