6,056 research outputs found
Morphological instability, evolution, and scaling in strained epitaxial films: An amplitude equation analysis of the phase field crystal model
Morphological properties of strained epitaxial films are examined through a
mesoscopic approach developed to incorporate both the film crystalline
structure and standard continuum theory. Film surface profiles and properties,
such as surface energy, liquid-solid miscibility gap and interface thickness,
are determined as a function of misfit strains and film elastic modulus. We
analyze the stress-driven instability of film surface morphology that leads to
the formation of strained islands. We find a universal scaling relationship
between the island size and misfit strain which shows a crossover from the
well-known continuum elasticity result at the weak strain to a behavior
governed by a "perfect" lattice relaxation condition. The strain at which the
crossover occurs is shown to be a function of liquid-solid interfacial
thickness, and an asymmetry between tensile and compressive strains is
observed. The film instability is found to be accompanied by mode coupling of
the complex amplitudes of the surface morphological profile, a factor
associated with the crystalline nature of the strained film but absent in
conventional continuum theory.Comment: 16 pages, 10 figures; to be published in Phys. Rev.
Entanglement and the modern Australian rhythm method: Lantana's lessons in policing sexuality and gender
Film in Australia, as with many other nations, is often seen as an important cultural medium where national stories about belonging and identity can be (re)produced in pleasurable and, at times, complicated ways. One such film is Ray Lawrence’s Lantana. Although striking a chord in Australia as a good film about ‘ basically good people’, people that rang ‘brilliantly’ true (Lantana DVD 2002), this paper argues that, at the same time as it produces a fantasy of a ‘good’ Australia, the film also conducts a regulation of what constitutes Australianness. In many ways the imaginary of Australia offered in this film, to its contemporary, urban, professional and intellectual elite audience, still draws on and (re)produces a vision of an Australian community that uses the same narrative frameworks of protection and control as the cruder discourses of ‘white Australia’ offered to an earlier generation of cinema-goers. This film’s central motif of the lantana bush, the out of control weed, that is known as both foreign and local is here emblematic of tensions about belonging, place and otherness. Yet while, within the film’s knowingly reflexive purview any remaining potential for racism is understood and itself under control – we know how to be good mutliculturalists –it is the trope of sexuality in Lantana that provides the real sense of edginess and anxiety about belonging. It is in this arena that the film sets up an idea of danger and –less self-consciously, and in the end more aggressively – marks out who is and who is not part of the community. In this context the motif of lantana signals an ambivalence about difference and the exotic. Lantana is both desirable because of the difference in its attractive Latin looks and repulsive or feared because of other qualities inherent within its difference: a refusal to behave and a propensity to get out-of control, spread and potentially take over. The film here explores desire for a taste of the other (a gay man, a newly separated woman, a Latin dance teacher). However, these fantasies are in the end emphatically shut down as the film ends by producing a vision of subtly normalised hetero, mono, familial (though not necessarily happy) forms of desiring, loving and reproducing in contemporary Australia
Phase field crystal dynamics for binary systems: Derivation from dynamical density functional theory, amplitude equation formalism, and applications to alloy heterostructures
The dynamics of phase field crystal (PFC) modeling is derived from dynamical
density functional theory (DDFT), for both single-component and binary systems.
The derivation is based on a truncation up to the three-point direct
correlation functions in DDFT, and the lowest order approximation using scale
analysis. The complete amplitude equation formalism for binary PFC is developed
to describe the coupled dynamics of slowly varying complex amplitudes of
structural profile, zeroth-mode average atomic density, and system
concentration field. Effects of noise (corresponding to stochastic amplitude
equations) and species-dependent atomic mobilities are also incorporated in
this formalism. Results of a sample application to the study of surface
segregation and interface intermixing in alloy heterostructures and strained
layer growth are presented, showing the effects of different atomic sizes and
mobilities of alloy components. A phenomenon of composition overshooting at the
interface is found, which can be connected to the surface segregation and
enrichment of one of the atomic components observed in recent experiments of
alloying heterostructures.Comment: 26 pages, 5 figures; submitted to Phys. Rev.
- …