We revisit submonolayer growth of C60 on Cu(111) by scanning tunneling microscopy (STM), with emphasis on the formation of higher-order commensurate metastable states. These phases show concomitant interfacial reconstruction, adlayer buckling, and adlayer rotation in order to match as closely as possible the 10.0 Å C60 nearest neighbor (NN) distance. Most interestingly, a clear correlation between the adlayer rotation angle and molecular contrast patterns is demonstrated. This is caused by the C60-induced reconstruction at preferred binding sites and adlayer buckling in adjustment to strain. Four contrast patterns, i.e., “disordered maze,” “linear-wall maze,” “p(√7 × √7), ” and “p(2 × 2), ” with increasing C60 NN distances are categorized. In the most compressed phase, buckling is favored and it is analogous to the ground state of a strongly-coupled antiferromagnetic system on a triangular lattice with alike adlayer buckling and interfacial corrugation. In contrast, the molecular orderings in the other structures are mostly dictated by lateral displacements of C60 toward preferred reconstructive binding sites. These metastable phases thus illustrate structural relaxation of a molecular layer on an adsorbate-induced reconstructed substrate in different adsorbate-adsorbate and adsorbate-substrate interaction limits.
|Number of pages||7|
|Journal||Physical Review B|
|Publication status||Published - 15 Mar 2004|