Please use this identifier to cite or link to this item:
|Type:||Artigo de evento|
|Title:||Cluster Expansion Failings When Applied To Semiconductor Superlattices|
|Abstract:||Cluster expansions (CE), by dealing only with short-range interactions, become inadequate when the interaction in the alloy is of long range. The classical example is the Madelung interaction (electrostatic energy) which, by decaying slowly with distance (1/r) cannot be described with any precision by CEs. Fortunately, in the case of semiconductors, charge neutrality is attained after a few atoms so that no 1/r term propagates far into the lattice. There are other long-range interactions, the strain energy due to alloying with different atomic sizes (1/r3), for instance, but this not a more important difficulty to CE than other interactions (the screened Coulomb, the exclusion principle, etc), as it will be shortly seen. In the case of semiconductors, an important test for CEs is how well they can perform with superlattices. This problem was studied before, at a time when the CE techniques were not so well developed. In what follows we show the results of several different CE applications to the wurtzite-based Ga1-xAlxN alloy system and to a model of strain energy, paying special attention to the superlattices and the special quasirandom structures SQS (A. Zunger, S.-H. Wei, L.G. Ferreira and J.E. Bernard, Phys. Rev. Lett 65, 353 (1990)). © 2007 WILEY-VCH Verlag GmbH & Co. KGaA.|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.