Year: 2014
Type: article
Abstract: In a cluster crystal, each lattice site is occupied by multiple soft-core particles. As the number density is increased at zero temperature, a "cascade" of isostructural phase transitions can occur between states whose site occupancy differs by unity. For low but finite temperature, each of these transitions terminates in a critical point. Using tailored Monte Carlo simulation techniques, we have studied such demixing cascades in systems of soft particles interacting via potentials of the generalized exponential form u(r) = ε exp [-(r/σ)(n)]. We have estimated the critical parameters of the first few transitions in the cascade as a function of the softness parameter n. The critical temperature and pressure exhibit non-monotonic behavior as n is varied, although the critical chemical potential remains monotonic. The trends for the pressure and chemical potential are confirmed by cell model calculations at zero temperature. As n → 2(+), all the transitions that we have observed are preempted by melting although we cannot rule out that clustering transitions survive at high density.
Source: The Journal of Chemical Physics
DOI: 10.1063/1.4894374
Authors: Nigel B. Wilding, Peter Sollich
Institutions: University of Bath, King's College London
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2032444053