 SQS: Special Quasirandom Structures 
Definition:  A technique to
simulate random
disorder in
finite sized
supercell 
Explanation:  The SQS approach is
used to investigate
substitutional
random alloys. In
SQS, randomness is
introduced by
mimicking as closely
as possible the
correlation
functions of an
infinite random
alloy within a
finite supercell. 
References:  A. Zunger, S.H. Wei, L. G. Ferreira, and J. E. Bernard, Phys. Rev. Lett. 65, 353 (1990) 

