Monte Carlo study of phase transitions and scattering intensities in a model of Au(110)

Disordered flat phase and phase diagram for restricted solid-on-solid models of fcc (110) surfaces

“…[3,4] Based on theoretical considerations and on simulation work, an interesting and nontrivial interplay has been anticipated between in-plane disordering, related to deconstruction, and vertical disordering, related to roughening, [5] and many other studies have been devoted to the problem. [6][7][8][9][10][11][12] The situation is, in principle, somewhat different for the two types of situations, i.e., the unreconstructed and the MR reconstructed cases. On an fcc (110) surface one can identify two interpenetrating rectangular sublattices, with origin, say, at 0 (the "white" sublattice) and A at ( √ 2x +ŷ +ẑ)a/2 (the "black" sublattice) where a is the lattice parameter,x = (001),ŷ = (110), andẑ = (110).…”

“…den Nijs has argued that, in such a case, the phase diagram should be qualitatively the same as that of a simple cubic (100) surface. [13] In particular, den Nijs, [13] Jug and Tosatti, [14] Kohanoff et al, [7] and Mazzeo et al [11] argued that (110) surfaces like those of Ag and Pd (which do not reconstruct) are good candidates for realizations of preroughening, a critical (non-universal) transition from a low temperature ordered phase to an intermediate disordered flat phase, previously identified in the context of restricted solid-on-solid models for simple cubic (100) surfaces. [15] In terms of the two ground states of the unreconstructed surface, the preroughening transition can be viewed as a disordering of the surface due to the proliferation of monoatomic steps (see Fig.…”

“…The question has been considered by Mazzeo et al, who have introduced, and studied by Monte Carlo simulation, a restricted SOS model which is able to deal with both unreconstructed and reconstructed situations. [11] Their model -which we will refer to as "K 3 -model" -is a simple modification of the exactly solvable body-centered solid-on-solid model (BCSOS) [17] obtained by adding a further neighbor interaction, which can stabilize the (2 × 1) MR reconstruction if required. For a reconstructed case, they find two-transitions: a 2D-Ising deconstruction to a disordered flat phase, and a KT roughening at a slightly higher temperature.…”

“…The unreconstructed case studied also shows two transitions, with a non-universal critical transition to a disordered flat phase followed by a KT roughening. [11] The nature of the disordered flat phase present in the model was, however, not fully characterized.…”

“…First we show that a quantum spin-1/2 hamiltonian also underlies the more general restricted SOS model where both the couplings considered in Refs. [11] and [18] are included. The spin-1/2 model is, in all cases, a Heisenberg chain with S z i S z j competing antiferromagnetic interactions ranging up to third neighbors.…”