Absolute surface energy determination

Surface Science, 1994

A correction is needed in Eqs. ( ) and (25b), which give the contribution of step-step interaction to the surface free energy in terms of the step diffusivity . Due to an inconsistent factor of two in a source reference [2], our equations include a factor of two error in the contribution of the step diffusivity, b 2. Thus, the correct form of Eq. ( ) is 7r 2kTb2(0, T)

Physical Review Letters, 2010

The link between the energy surface of bulk systems and their dynamical properties is generally difficult to establish. Using the activation-relaxation technique, we follow the change in the barrier distribution of a model of amorphous silicon as a function of the degree of global relaxation. We find that while the barrier-height distribution, calculated from the initial minimum, is a unique function that depends only on the level of relaxation, the reverse-barrier height distribution, calculated from the final state, is independent of global relaxation, following a different function. Moreover, the resulting gained or released energy distribution is a simple convolution of these two distributions indicating that the activation and relaxation parts of the elementary relaxation mechanism are completely independent. This characterized energy landscape can be used to explain nanocalorimetry measurements.

Some aspects of the thermodynamics and mechanics of solid surfaces, in particular with respect to surface stress and surface energy, are reviewed. The purpose is to enlighten the deep differences between these two physical quantities. We consider successively the case of atomic flat surfaces and the case of vicinal surfaces characterized by surface stress discontinuities. Finally, experimental examples, concerning Si surfaces, are described.

Physical Review B, 1998

We study the equilibrium fluctuation properties of a step on the 2ϫ1-reconstructed Si͑001͒ surface, by using the two-dimensional restricted solid-on-solid model. We propose a new approach to calculate the angledependent step tension ␥͑͒ ͑ : mean running direction of the step, relative to the crystal axis͒ where the numerical renormalization-group technique and the temperature-rescaled Ising-model-interface ansatz for step fluctuations are combined. From the calculated ␥͑͒ we obtain the step stiffness ␥()ϩ‫ץ‬ 2 ‫ץ/)(␥‬ 2 , which is in good agreement with experimental observation. ͓S0163-1829͑98͒51708-0͔ RAPID COMMUNICATIONS

Surface Science, 1988

Physical Review B, 1996

Scanning tunneling microscopy images of 4.5°misoriented double B stepped Si͑001͒ have been analyzed to determine the double-layer step-edge formation energies of the energetically stable double step (B-type͒ as well as the energetically unstable double step (A-type͒. The ordering of the various single-and double-layer step-edge formation energies is in accordance with semiempirical tight-binding-based total-energy calculations performed by Chadi ͓Phys. Rev. Lett. 59, 1691 ͑1987͔͒. Finally, the miscut angle at which the transition between the single-and double-layer stepped surface occurs as calculated using the experimentally obtained step-edge formation energies is in agreement with the experiments. ͓S0163-1829͑96͒05724-4͔

Physical Review B, 1998

We present an ab initio exploration of the phenomena which will become important for freestanding structures of silicon as they are realized on the nanoscale. We find that not only surface but also edge effects are important considerations in structures of dimensions ∼3 nm. Specifically, for long nanoscale silicon bars, we find two competing low-energy reconstructions with a transition from one to the other as the cross section of the bar decreases. We predict that this size-dependent phase transition has a signature in the electronic structure of the bar but little effect on elastic properties. PACS 68.35.Bs 68.35.Rh

Surface Science, 1998

We have used density functional theory to establish a database of surface energies for low index surfaces of 60 metals in the periodic table. The data may be used as a consistent starting point for models of surface science phenomena. The accuracy of the database is established in a comparison with other density functional theory results and the calculated surface energy anisotropies are applied in a determination of the equilibrium shape of nano-crystals of Fe,

Surface Science, 2002

The well-annealed and quenched Si(1 0 5), (1 0 4), (1 0 3), and (3 1 9) surfaces have been studied with LEED and STM, and it turns out that the morphology and reconstruction of all these surfaces exhibit a rich temperature dependence, especially for Si(1 0 5). A technique based on LEED pattern analysis has been developed, which can tell if the unit cell of a stable surface consists of nanofacets of other (major) stable surfaces, to discriminate minor from major stable surfaces. By means of this technique, Si(1 0 5) and (1 0 3) have been disclosed to be minor stable surfaces and belong to the (0 0 1) family, and their unit cell structures as well as the step configurations of many reconstructions observed here have been mapped out without invoking models. The rarely seen temperature dependent step configurations of Si(1 0 5) are interpreted as a result of the interplay of the entropic repulsive, short-range attractive, and longrange repulsive step-step interactions. The fact that Si(1 0 3) belongs to the (0 0 1) family whereas Ge(1 0 3) belongs to the (1 1 3) family is attributed to the difference between the surface structure of Ge(1 1 3)3 Â 2 and that of the Si(1 1 3)3 Â 2.