This review summarizes recent developments in the theory of spin glasses, as well as pertinent experimental data. The most characteristic properties of spin glass systems are described, and related phenomena in other glassy systems (dielectric and orientational glasses) are mentioned. The Edwards-Anderson model of spin glasses and its treatment within the replica method and mean-field theory are outlined, and concepts such as "frustration," "broken replica symmetry," "broken ergodicity," etc., are discussed. The dynamic approach to describing the spin glass transition is emphasized. Monte Carlo simulations of spin glasses and the insight gained by them are described. Other topics discussed include site-disorder models, phenomenological theories for the frozen phase and its excitations, phase diagrams in which spin glass order and ferromagnetism or antiferromagnetism compete, the Ne\'el model of superparamagnetism and related approaches, and possible connections between spin glasses and other topics in the theory of disordered condensed-matter systems.

Spin glasses: Experimental facts, theoretical concepts, and open questions

The structural properties of free nanoclusters are reviewed. Special attention is paid to the interplay of energetic, thermodynamic, and kinetic factors in the explanation of cluster structures that are actually observed in experiments. The review starts with a brief summary of the experimental methods for the production of free nanoclusters and then considers theoretical and simulation issues, always discussed in close connection with the experimental results. The energetic properties are treated first, along with methods for modeling elementary constituent interactions and for global optimization on the cluster potential-energy surface. After that, a section on cluster thermodynamics follows. The discussion includes the analysis of solid-solid structural transitions and of melting, with its size dependence. The last section is devoted to the growth kinetics of free nanoclusters and treats the growth of isolated clusters and their coalescence. Several specific systems are analyzed.

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Structural properties of nanoclusters: Energetic, thermodynamic, and kinetic effects

The ever increasing requirements for electrical performance of on-chip wiring has driven three major technological advances in recent years. First, copper has replaced Aluminum as the new interconnect metal of choice, forcing also the introduction of damascene processing. Second, alternatives for SiO2 with a lower dielectric constant are being developed and introduced in main stream processing. The many new resulting materials needs to be classified in terms of their materials characteristics, evaluated in terms of their properties, and tested for process compatibility. Third, in an attempt to lower the dielectric constant even more, porosity is being introduced into these new materials. The study of processes such as plasma interactions and swelling in liquid media now becomes critical. Furthermore, pore sealing and the deposition of a thin continuous copper diffusion barrier on a porous dielectric are of prime importance. This review is an attempt to give an overview of the classification, the character...

Low dielectric constant materials for microelectronics

This is an introductory review of the physics of quantum spin liquid states. Quantum magnetism is a rapidly evolving field, and recent developments reveal that the ground states and low-energy physics of frustrated spin systems may develop many exotic behaviors once we leave the regime of semiclassical approaches. The purpose of this article is to introduce these developments. The article begins by explaining how semiclassical approaches fail once quantum mechanics become important and then describe the alternative approaches for addressing the problem. Mainly spin-1/2 systems are discussed, and most of the time is spent in this article on one particular set of plausible spin liquid states in which spins are represented by fermions. These states are spin-singlet states and may be viewed as an extension of Fermi liquid states to Mott insulators, and they are usually classified in the category of so-called SU(2), U(1), or Z2 spin liquid states. A review is given of the basic theory regarding these states and the extensions of these states to include the effect of spin-orbit coupling and to higher spin (S>1/2) systems. Two other important approaches with strong influences on the understanding of spin liquid states are also introduced: (i) matrix product states and projected entangled pair states and (ii) the Kitaev honeycomb model. Experimental progress concerning spin liquid states in realistic materials, including anisotropic triangular-lattice systems [κ-(ET)2Cu2(CN)3 and EtMe3Sb[Pd(dmit)2]2], kagome-lattice system [ZnCu3(OH)6Cl2], and hyperkagome lattice system (Na4Ir3O8), is reviewed and compared against the corresponding theories.

Quantum spin liquid states

Basic characteristics of the liquid-glass transition are reviewed, emphasizing its universality and briefly summarizing the most popular phenomenological models. Discussion is focused on a number of alternative models which one way or the other connect the fast and slow degrees of freedom of viscous liquids. It is shown that all these ``elastic'' models are equivalent in the simplest approximation.

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Colloquium : The glass transition and elastic models of glass-forming liquids

Preface List of symbols 1. Morphology of a crystal surface 2. Surface free energy, step free energy, and chemical potential 3. The equilibrium crystal shape 4. Growth and dissolution crystal shapes: Frank's model 5. Crystal growth: the abc 6. Growth and evaporation of a stepped surface 7. Diffusion 8. Thermal smoothing of a surface 9. Silicon and other semiconducting materials 10. Growth instabilities of a planar front 11. Nucleation and the adatom diffusion length 12. Growth roughness at long lengthscales in the linear approximation 13. The Kardar-Parisi-Zhang equation 14. Growth without evaporation 15. Elastic interactions between defects on a crystal surface 16. General equations of an elastic solid 17. Technology, crystal growth and surface science Appendices References Index.

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Physics of crystal growth

A generalized frustrated Ising model on a two-dimensional lattice is considered. This model is paramagnetic at zero temperature but ferromagnetic provided 0 < T < T c. The effect of dilution on this system is also investigated, and long range order is shown to be restored in the dilute model under certain conditions involving concentration, temperature and interactions which are discussed in comparison with usual percolation.

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Order as an effect of disorder

Continuum equations appropriate to describe crystal growth from atom beams are derived in various cases. When desorption is important, the growth is described on very long lengthscales by the Kardar-Parisi-Zhang equation, but should be corrected for shorter lengthscales where surface diffusion is the dominant mechanism. In the absence of desorption, an important effect at sufficiently low temperature comes from the fact that diffusion of incoming atoms on the surface is anisotropic on long lengthscales becaused it is biased by reflexions against terrace edges. As a result, the growth is described by a pseudo-diffusion equation. In the case of a high symmetry surface, (001) or (ill), an instability arises. Finally,in the absence of diffusion bias, the growth is described by a nonlinear equation of fourth order with respect to 3/3x and 3/3y. The exponents are calculated in a Flory-type approximation. In particular the roughness exponent is found to be x = (5 d)/3 in d dimensions.

https://hal.archives-ouvertes.fr/jpa-00246302/document

Continuum models of crystal growth from atomic beams with and without desorption

A simple growth model is investigated where particles are deposited onto a substrate randomly and subsequently relax into a position nearby where the binding is strongest. In space dimension d = 2 the surface roughness exponent and the dynamical exponent are ξ = 1.4 ± 0.1 and z = 3.8 ± 0.5. These values are larger than for previous models of sedimentation or ballistic deposition and are surprisingly close to the ones obtained from a linear generalized Langevin equation for growth with surface diffusion. A scaling relation 2ξ = z − d + 1 is proposed to be valid for a large class of growth models relevant for molecular beam epitaxy.

https://iopscience.iop.org/article/10.1209/0295-5075/13/5/002/pdf

Growth with Surface Diffusion

Magnetic systems with competing ferromagnetic and antiferromagnetic inter- actions are investigated and a few exact results are obtained. The possibility of exact solutions comes from the fact that the distribution of ferro- and antiferromagnetic bonds is assumed to obey certain rules, instead of being completely random. The ground state, however, has the character of a spin glass. Two of our models have the property that they have no phase transi- tion in the case of one-dimensional (Ising) spins, whereas there is a phase transition for two- dimensional (XY) spins. The phase transition disappears again for high values of the spin dimensionality n. In a particular case of a three-dimensional. X Y model, the susceptibility has been calculated at high and IOW temperatures; it has a maximum at some temperature, but a speculative argument is given that there is actually no kink.

http://iopscience.iop.org/article/10.1088/0022-3719/10/10/014/pdf

Jacques Villain

Papers

Physics of crystal growth

Order as an effect of disorder

Continuum models of crystal growth from atomic beams with and without desorption

Growth with Surface Diffusion

Spin glass with non-random interactions