Critical exponents and unusual properties of the broken phase in the 3d-RP2 antiferromagnetic model
We present the results of a Monte Carlo simulation of the antiferromagnetic RP^2 model in three dimensions. 
With finite-size scaling techniques we accurately measure the critical exponents and compare them with those of 
O(N) models. We are able to parameterize the corrections-to-scaling. The symmetry properties of the broken 
phase are also studied.
Nonuniversality in helical and canted-spin systems.
Vector-spin models with competing interactions have in general nontrivial ground states which completely break rotational invariance. We study the prototypical stacked triangular Heisenberg antiferromagnet by means of a O(3)×O(2)/O(2) nonlinear σ model in a 2+e expansion. We find a dynamically generated O(4) symmetry. We propose that such systems in three dimensions have a first-order transition or a second-order one with either N=4 or tricritical mean-field exponents. We argue that this view is supported by experimental and numerical data
Anomalous Annealing Behavior of Arsenic Implanted Silicon as a Function of Dose and Energy
Anomalous annealing behavior of damage in As implanted Si has been investigated by channeling effect measurements. Room temperature As implants with doses from 1014 to 2 × 1016cm-2 at energies ranging from 50 to 250 keV into Si were annealed over the range of 600°C to 1100°C. Anneal temperatures ≥ 950°C reduce the disorder for ion doses of 0.5 to 1 × 1016 cm-2 at energies between 50 and 250 keV. Anomalously high residual disorder was found for the intermediate doses of 2 × 1014 to 2 × 10/cm2 implanted above 100 keV. For this intermediate dose, annealing of implants performed at liquid nitrogen temperatures did not show significant reduction in this damage. However implants at 200° to 300°C indicate a lower amount of damage compared to the room temperature implants.