{'fraction_non_alphanumeric': 0.047453703703703706, 'fraction_numerical': 0.0011574074074074073, 'mean_word_length': 5.407407407407407, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
The energetics of surface-alloy formation: an embedded-atom-method, second-order-expansion study

Chemical ordering and clustering instabilities in alloys are governed by the Fourier transform of the effective pair interactions, V(k). We make use of a second-order-expansion formalism, based upon embedded-atom-method interatomic potentials, to calculate chemical and elastic contributions to V(k) for monolayer surface alloys on single-crystal substrates. It is demonstrated that the elastic contribution to V(k) is characterized by a finite slope at the origin, consistent with continuum models which predict that V(k)∝-|k| for small wavevectors. As a consequence, the global minimum in V(k) always occurs at finite k, and therefore compositional instabilities in ultrathin surface-alloy films are generally of an ordering (as opposed to clustering, k = 0) type.