Title: Effect of increasing disorder on domains of the two-dimensional Coulomb glass,
Abstract: We have studied a two dimensional lattice model of Coulomb glass for a wide
range of disorders at $T\sim 0$. The system was first annealed using Monte
Carlo simulation. Further minimization of the total energy of the system was
done using Baranovskii et al algorithm followed by cluster flipping to obtain
the pseudo ground states. We have shown that the energy required to create a
domain of linear size L in d dimensions is proportional to $L^{d-1}$. Using
Imry-Ma arguments given for random field Ising model, one gets critical
dimension $d_{c}\geq 2$ for Coulomb glass. The investigations of domains in the
transition region shows a discontinuity in staggered magnetization which is an
indication of a first-order type transition from charge-ordered phase to
disordered phase. The structure and nature of Random field fluctuations of the
second largest domain in Coulomb glass are inconsistent with the assumptions of
Imry and Ma as was also reported for random field Ising model. The study of
domains showed that in the transition region there were mostly two large
domains and as disorder was increased, the two large domains remained but there
were a large number of small domains. We have also studied the properties of
the second largest domain as a function of disorder. We furthermore analysed
the effect of disorder on the density of states and showed a transition from
hard gap at low disorders to a soft gap at higher disorders. At $W=2$, we have
analysed the soft gap in detail and found that the density of states deviates
slightly ($\delta\approx 1.293 \pm 0.027$) from the linear behaviour in two
dimensions. Analysis of local minima show that the pseudo ground states have
similar structure.